JP2016075642A - Method and apparatus for making propeller related characteristic of free-running model ship similar to that of actual ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make propeller related characteristics of a free-running model ship similar to those of an actual ship.SOLUTION: On the basis of basic performance estimation of an actual ship, ship speed which varies under external force of a free-running model ship is measured and on the basis of the measured ship speed, propeller rotation frequency of the free-running model ship and output of auxiliary thrust means are controlled, thereby making propeller related characteristics of the free-running model ship under external force similar to those of the actual ship.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for making a propulsion unit-related characteristic of a free-running model ship similar to a real ship in a self-propelled test of a model ship, and a propulsion unit-related characteristic real ship similarity device for a free-running model ship.

  A free-running model test method in which friction correction equivalent to that of a self-propulsion test in a towed water tank is performed using an auxiliary thrust device is disclosed (Patent Document 1). When a free-running model ship is accompanied by steering, or when disturbances such as waves and winds are applied, the ship speed may change from moment to moment due to turning and tilting induced by these. Even under such circumstances, the friction can be corrected by generating an auxiliary thrust according to the ship speed every moment.

  Friction correction originally secures a mechanical similarity law for propeller propulsive force by making the propeller load of the model ship similar to that of the actual ship, and the effective wake ratio, propeller of the actual ship is verified by model tests under that condition. It is one of the methods used to estimate ship propulsion performance such as efficiency ratio and effective horsepower.

  Further, a free-running model test method is disclosed in which a friction correction thrust can be generated straightly backward with respect to the model ship by compressed nitrogen gas or the like, and the source of the friction correction thrust is not mounted on the model hull (Patent Document 2). ). Furthermore, a model ship test apparatus is disclosed in which the model ship navigation plan can be changed by remote control from the model ship (Patent Document 3).

  On the other hand, the free-running model test is generally performed not only for examining propulsion performance but also for the purpose of examining performance other than propulsion performance, such as a steering performance test.

  In a pilot performance test using a conventional free-running model ship that is not equipped with an auxiliary thrust device, the propeller load of the model ship is relatively larger than that of the actual ship, so the rudder effectiveness is relatively higher than that of the actual ship. It is known to improve. In other words, the conventional maneuverability test results using a free-running model ship cannot be regarded as the actual ship maneuvering performance.

  As a method for more reasonably estimating the maneuvering performance of an actual ship, a model ship with a propeller and rudder that can freely travel is used, and only auxiliary thrust is added to the model ship to ensure the similarity of rudder effectiveness. As described above, a technique is disclosed in which only the auxiliary thrust calculated based on the ship speed is controlled to ensure the similarity of the steering effect to the actual ship in the model ship (Non-patent Document 1).

JP 2012-112878 A JP 2001-174364 A JP 2009-264781 A

Michio Ueno, Yoshiaki Tsukada, Katsuharu Tanizawa, Yasushi Kitagawa; Proceedings of the 16th Annual Meeting of the Japan Society of Marine Science and Technology, pp. 325-326.

  By the way, in order to reproduce a model ship with a ship speed response similar to that of an actual ship, the measurement is performed while measuring the ship's longitudinal components that change under external force based on the actual performance estimation of the actual ship. It is necessary to control both the propeller rotation speed and the output of the auxiliary thrust device based on the data.

  In addition, a decrease in ship speed due to external forces such as waves and wind belongs to one of the basic performances of the ship and is an important factor that affects the operation plan. In recent years, regulations aimed at reducing greenhouse gas emissions from ships have been started mainly by the United Nations Maritime Organization, and the rate of ship speed reduction in an actual sea area where waves and winds coexist is also taken into consideration for the indicators. Has been. On the other hand, while the development of ships with low fuel consumption that satisfy the regulations of the United Nations Maritime Organization is progressing, ships equipped with engines with lower output than necessary become impossible to maneuver under stormy weather, leading to maritime accidents It is pointed out that the possibility increases.

  At present, estimation calculation is the only method for estimating how much the ship speed drops under stormy weather and how rough the sea can be. Based on the results of research on the increase in resistance in the waves, it is considered that the estimation calculation for ship speed reduction during normal navigation under external force has reached a practical level. However, unlike the ship speed drop during normal navigation, in a situation where the ship speed drops to near impossible to maneuver under stormy weather, it accurately estimates not only the longitudinal component of the ship of the external force but also the lateral component and turning moment component, Furthermore, it is necessary to estimate the navigational state of the ship including the steering force. However, practical estimation methods for the left-right direction component and the turning moment component of wave drift force are not established at this stage.

  The present invention uses a free-running model ship capable of controlling the propeller rotation speed during navigation and the output of auxiliary thrust means, and propulsion of a free-running model ship whose characteristics related to the propeller under external force are similar to those of the actual ship. A method for making vessel-related characteristics similar to actual ships and a propulsion unit-related characteristics actual ship similarity device for a free-running model ship are provided.

  The method for making the propulsion unit related characteristics of a free-running model ship according to claim 1 of the present invention similar to an actual ship is based on the basic performance estimation of an actual ship and changes under the external force of the free-running model ship. The propulsion speed of the free-running model ship and the output of the auxiliary thrust means are controlled based on the measured ship speed, and the propeller-related characteristics under the external force of the free-running model ship are measured. It is characterized by being similar to.

ｔ_ｓ ：実船の推力減少率
Ｔ’ｓ ： 実船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
ｔ_ｍ ：自由航走模型船の推力減少率
Ｔ’_ｍ ：自由航走模型船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
ｆ_ＴＡ ：補助推力係数
Ｔ’_ＳＦＣ：摩擦修正に必要な力（無次元値、船速の関数）
を基に導出される前記自由航走模型船のプロペラ回転数と補助推力係数ｆ_ＴＡに基づき制御することが好適である。 Here, the output of the propeller rotation speed and the auxiliary thrust means of the free-running model ship,

t _s: actual ship thrust reduction rate T's: propeller propulsion of the actual ship (dimensionless value, a function of the propeller speed and boat speed)
t _m : Thrust reduction rate of a free-running model ship T ' _m : Propeller propulsion force of a free-running model ship (dimension value, function of propeller rotation speed and ship speed)
f _TA : Auxiliary thrust coefficient T ' _SFC : Force required for friction correction (dimension value, function of ship speed)
It is preferred to the basis of the propeller speed of the free sailing model ship and the auxiliary thrust coefficient f _TA control derived based on.

  In addition, it is preferable that the basic performance estimation of the actual ship includes any change in propeller rotation speed including constant propeller rotation speed, constant propeller torque, constant propeller output, or reverse rotation.

  In addition, in the case where similarity of steering / slope navigation / turning resistance is not necessary or separately secured, considering the similarity of propeller propulsion force under the external force of the actual ship and the free-running model ship, It is preferable to ensure the similarity of the speed response of the free-running model ship.

Ｔｓ’ ： 実船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
Ｔ_ｍ’ ：自由航走模型船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
で表される前記プロペラ推進力の相似性を確保するために前記補助推力係数ｆ_ＴＡを１として前記自由航走模型船のプロペラ回転数を求めて制御することが好適である。 In particular,

Ts': Propeller propulsive force of actual ship (dimensionless value, propeller rotation speed and ship speed function)
T _m ' : Propeller propulsion force of a free-running model ship (dimension value, function of propeller rotation speed and ship speed)
In order to ensure the similarity of the propeller propulsion force represented by the formula (1), it is preferable that the auxiliary thrust coefficient _{fTA is set} to 1 to determine and control the propeller rotational speed of the free-running model ship.

  In addition, when similarity of steering / slope / turning resistance is not required or when similarity of steering / slope / turning resistance is ensured separately, the propeller under the external force of the actual ship and the free-running model ship is used. It is preferable to ensure the similarity of the speed response of the free-running model ship based on the similarity of torque.

Ｑ_Ｓ’ ：実船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
Ｑ_ｍ’ ：自由航走模型船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することが好適である。 Specifically, the mathematical formula (1) and

Q _S ': Propeller torque of actual ship (dimensionless value, function of propeller rotation speed and ship speed)
Q _m ': Propeller torque of a free-running model ship (dimensionless value, function of propeller rotation speed and ship speed)
It is preferable that the propeller rotational speed of the free-running model ship and the auxiliary thrust coefficient _fTA are obtained and controlled.

  In addition, when similarity of steering / slope / turning resistance is not required or when similarity of steering / slope / turning resistance is ensured separately, the propeller under the external force of the actual ship and the free-running model ship is used. It is preferable to ensure the similarity of the ship speed response of the free-running model ship based on the similarity of the rotational speed.

ｎ_ｓ’：実船のプロペラ回転数（無次元値）
ｎ_ｍ’： 自由航走模型船のプロペラ回転数（無次元値）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することが好適である。 Specifically, the mathematical formula (1) and

_ns ': Propeller rotation speed of actual ship (dimensionless value)
n _m ': Propeller rotation speed of a free-running model ship (dimensionless value)
It is preferable that the propeller rotational speed of the free-running model ship and the auxiliary thrust coefficient _fTA are obtained and controlled.

  In addition, when the similarity of steering / slope navigation / turning resistance is not necessary or when similarity of steering / slope navigation / turning resistance is ensured separately, the horsepower under the external force of the actual ship and the free-running model ship It is preferable to ensure the similarity of the ship speed response of the free-running model ship based on the similarity.

ｎ_ｓ’ ：実船のプロペラ回転数（無次元値）
Ｑ_Ｓ’ ：実船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
ｎ_ｍ’ ：自由航走模型船のプロペラ回転数（無次元値）
Ｑ_ｍ’ ：自由航走模型船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することが好適である。 Specifically, the mathematical formula (1) and

n _s ': Propeller rotation speed of actual ship (dimensionless value)
Q _S ': Propeller torque of actual ship (dimensionless value, function of propeller rotation speed and ship speed)
n _m ': Propeller rotation speed of a free-running model ship (dimensionless value)
Q _m ': Propeller torque of a free-running model ship (dimensionless value, function of propeller rotation speed and ship speed)
It is preferable that the propeller rotational speed of the free-running model ship and the auxiliary thrust coefficient _fTA are obtained and controlled.

  In addition, when similarity of steering / slope / turning resistance is not required or when similarity of steering / slope / turning resistance is ensured separately, the propeller under the external force of the actual ship and the free-running model ship is used. It is preferable that the similarity of the ship speed response of the free-running model ship is ensured by matching the slip ratio.

Ｓ_ｓ：実船のプロペラスリップ比（プロペラ回転数と船速の関数）
Ｓ_ｍ：自由航走模型船のプロペラスリップ比（プロペラ回転数と船速の関数）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することが好適である。 Specifically, the mathematical formula (1) and

S _s : Propeller slip ratio of actual ship (propeller speed and ship speed function)
S _m : Propeller slip ratio of a free-running model ship (function of propeller rotation speed and ship speed)
It is preferable that the propeller rotational speed of the free-running model ship and the auxiliary thrust coefficient _fTA are obtained and controlled.

  15. A propulsion device-related characteristic actual ship similarity device for a free-running model ship according to claim 14, a free-running model ship having a propeller and auxiliary thrust means, and a ship for measuring the speed of the free-running model ship Speed measuring means and control means for controlling the propeller rotation speed of the propeller and the output of the auxiliary thrust means based on the estimated basic performance of the actual ship and the measured ship speed, and under the external force of the free-running model ship The propulsion device-related characteristics in are similar to those of the actual ship.

  Here, it is preferable that the control means executes a method of making the propulsion unit related characteristics of the free-running model ship similar to an actual ship.

Further, the control means, the ship speed of the free sailing model ship previously obtained the free cruising model ship propeller speed and the auxiliary thrust coefficient f _TA by a method of the thruster associated properties actual ship similarity of It is preferable to store and control the relationship between

  Further, it is preferable that the ship speed measuring means measures a longitudinal component of a ship speed of the free-running model ship.

  According to the method for making the propulsion unit-related characteristics of a free-running model ship according to claim 1 of the present invention similar to an actual ship, it changes under the external force of the free-running model ship based on the basic performance estimation of the actual ship. The propulsion speed of the free-running model ship and the output of the auxiliary thrust means are controlled based on the measured ship speed, and the propeller-related characteristics under the external force of the free-running model ship are measured. By making it similar to an actual ship, a maneuvering performance test under an external force can be performed using a model ship, and the maneuvering characteristics of the actual ship under an external force can be estimated and confirmed.

ｔ_ｓ ：実船の推力減少率
Ｔ’ｓ ： 実船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
ｔ_ｍ ：自由航走模型船の推力減少率
Ｔ’_ｍ ：自由航走模型船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
ｆ_ＴＡ ：補助推力係数
Ｔ’_ＳＦＣ：摩擦修正に必要な力（無次元値、船速の関数）
を基に導出される前記自由航走模型船のプロペラ回転数と補助推力係数ｆ_ＴＡに基づき制御することによって、模型船を用いて実船の操船特性を推定及び確認する具体的な方法を提供することができる。 Here, the output of the propeller rotation speed and the auxiliary thrust means of the free-running model ship,

t _s: actual ship thrust reduction rate T's: propeller propulsion of the actual ship (dimensionless value, a function of the propeller speed and boat speed)
t _m : Thrust reduction rate of a free-running model ship T ' _m : Propeller propulsion force of a free-running model ship (dimension value, function of propeller rotation speed and ship speed)
f _TA : Auxiliary thrust coefficient T ' _SFC : Force required for friction correction (dimension value, function of ship speed)
By controlling basis the propeller rotational speed of the free-sailing model ship and the auxiliary thrust coefficient f _TA derived based on, providing a specific method for estimating and confirming the maneuvering characteristics of the actual ship using a model ship can do.

  In addition, the basic performance estimation of the actual ship includes any propeller speed change including constant propeller speed, constant propeller torque, constant propeller output, or reverse rotation. A maneuvering performance test to estimate and confirm the maneuvering characteristics can be performed.

  In addition, in the case where similarity of steering / slope navigation / turning resistance is not necessary or separately secured, considering the similarity of propeller propulsion force under the external force of the actual ship and the free-running model ship, A maneuverability test that estimates and confirms the maneuvering characteristics of an actual ship using a model ship under similar conditions of speed change and propeller propulsion by ensuring similarity in ship speed response of a free-running model ship Can be implemented.

Ｔｓ’ ： 実船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
Ｔ_ｍ’ ：自由航走模型船のプロペラ推進力（無次元値、プロペラ回転数と船速の関数）
で表される前記プロペラ推進力の相似性を確保するために前記補助推力係数ｆ_ＴＡを１として前記自由航走模型船のプロペラ回転数を求めて制御することによって、船速変化とプロペラ推進力を相似にした条件下において模型船を用いて実船の操船特性を推定及び確認する操縦性能試験を実施する具体的な方法を提供することができる。 In particular,

Ts': Propeller propulsive force of actual ship (dimensionless value, propeller rotation speed and ship speed function)
T _m ' : Propeller propulsion force of a free-running model ship (dimension value, function of propeller rotation speed and ship speed)
In order to ensure the similarity of the propeller propulsion force represented by the following formula, the auxiliary thrust coefficient _{fTA is set} to 1 to obtain and control the propeller rotational speed of the free-running model ship, thereby controlling the change in ship speed and the propeller propulsion force. It is possible to provide a specific method for conducting a maneuverability test for estimating and confirming the maneuvering characteristics of an actual ship using a model ship under similar conditions.

  In addition, when similarity of steering / slope / turning resistance is not required or when similarity of steering / slope / turning resistance is ensured separately, the propeller under the external force of the actual ship and the free-running model ship is used. By ensuring the similarity of the ship speed response of the free-running model ship based on the similarity of torque, the ship maneuvering characteristics of the actual ship can be measured using the model ship under the conditions where the ship speed change and the propeller torque are similar. A pilot performance test can be performed to estimate and confirm.

Ｑ_Ｓ’ ：実船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
Ｑ_ｍ’ ：自由航走模型船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することによって、船速変化とプロペラトルクを相似にした条件下において模型船を用いて実船の操船特性を推定及び確認する操縦性能試験を実施する具体的な方法を提供することができる。 Specifically, the mathematical formula (7) and

Q _S ': Propeller torque of actual ship (dimensionless value, function of propeller rotation speed and ship speed)
Q _m ': Propeller torque of a free-running model ship (dimensionless value, function of propeller rotation speed and ship speed)
It said free cruising propeller speed of a model ship and by the controlled seek auxiliary thrust coefficient f _TA, actual using model ship under conditions in which the boat speed change and the propeller torque similar ship be simultaneous with It is possible to provide a specific method for conducting a maneuvering performance test for estimating and confirming the ship maneuvering characteristics.

  In addition, when similarity of steering / slope / turning resistance is not required or when similarity of steering / slope / turning resistance is ensured separately, the propeller under the external force of the actual ship and the free-running model ship is used. By ensuring the similarity of the ship speed response of the free-running model ship based on the similarity of the rotational speed, the maneuvering of the actual ship using the model ship under the condition that the ship speed change and the propeller rotational speed are similar A maneuverability test can be performed to estimate and confirm the characteristics.

ｎ_ｓ’：実船のプロペラ回転数（無次元値）
ｎ_ｍ’： 自由航走模型船のプロペラ回転数（無次元値）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することによって、船速変化とプロペラ回転数を相似にした条件下において模型船を用いて実船の操船特性を推定及び確認する操縦性能試験を実施する具体的な方法を提供することができる。 Specifically, the mathematical formula (7) and

_ns ': Propeller rotation speed of actual ship (dimensionless value)
n _m ': Propeller rotation speed of a free-running model ship (dimensionless value)
Wherein by controlling seeking propeller speed free sailing model ship and the auxiliary thrust coefficient f _TA, using a model ship under conditions in which the boat speed changes and propeller speed in similar by causing simultaneous real A specific method for conducting a maneuvering performance test for estimating and confirming the maneuvering characteristics of the ship can be provided.

  In addition, when the similarity of steering / slope navigation / turning resistance is not necessary or when similarity of steering / slope navigation / turning resistance is ensured separately, the horsepower under the external force of the actual ship and the free-running model ship By ensuring the similarity of the speed response of the free-running model ship based on the similarity of the ship, the ship maneuvering characteristics of the actual ship were estimated using the model ship under conditions similar to the ship speed change and horsepower. It is possible to provide a specific method for performing the steering performance test to be confirmed.

ｎ_ｓ’ ：実船のプロペラ回転数（無次元値）
Ｑ_Ｓ’ ：実船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
ｎ_ｍ’ ：自由航走模型船のプロペラ回転数（無次元値）
Ｑ_ｍ’ ：自由航走模型船のプロペラトルク（無次元値、プロペラ回転数と船速の関数）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することによって、船速変化と馬力を相似にした条件下において模型船を用いて実船の操船特性を推定及び確認する操縦性能試験を実施する具体的な方法を提供することができる。 Specifically, the mathematical formula (7) and

n _s ': Propeller rotation speed of actual ship (dimensionless value)
Q _S ': Propeller torque of actual ship (dimensionless value, function of propeller rotation speed and ship speed)
n _m ': Propeller rotation speed of a free-running model ship (dimensionless value)
Q _m ': Propeller torque of a free-running model ship (dimensionless value, function of propeller rotation speed and ship speed)
By controlling seeking the auxiliary thrust coefficient f _TA and propeller speed of said free cruising model ship by causing simultaneous equations, using a model ship under conditions in which the boat speed changes and horsepower similarity of actual ship A specific method for conducting a maneuvering performance test for estimating and confirming the maneuvering characteristics can be provided.

  In addition, when similarity of steering / slope / turning resistance is not required or when similarity of steering / slope / turning resistance is ensured separately, the propeller under the external force of the actual ship and the free-running model ship is used. By matching the slip ratio and ensuring the similarity of the speed response of the free-running model ship, it is possible to operate the actual ship using the model ship under the condition that the propeller slip ratio is matched with the similarity of the ship speed change. A specific method for conducting a maneuverability test to estimate and confirm characteristics can be provided.

Ｓ_ｓ：実船のプロペラスリップ比（プロペラ回転数と船速の関数）
Ｓ_ｍ：自由航走模型船のプロペラスリップ比（プロペラ回転数と船速の関数）
を連立させることで前記自由航走模型船のプロペラ回転数と前記補助推力係数ｆ_ＴＡを求めて制御することによって、船速変化の相似と共にプロペラスリップ比を一致させた条件下において模型船を用いて実船の操船特性を推定及び確認する操縦性能試験を実施する具体的な方法を提供することができる。 Specifically, the mathematical formula (7) and

S _s : Propeller slip ratio of actual ship (propeller speed and ship speed function)
S _m : Propeller slip ratio of a free-running model ship (function of propeller rotation speed and ship speed)
The model ship is used under the condition where the propeller slip ratio is matched with the similarity of the ship speed by _obtaining and controlling the propeller rotation speed and the auxiliary thrust coefficient fTA of the free-running model ship Thus, it is possible to provide a specific method for conducting a maneuvering performance test for estimating and confirming the maneuvering characteristics of an actual ship.

  15. A propulsion device-related characteristic actual ship similarity device for a free-running model ship according to claim 14, a free-running model ship having a propeller and auxiliary thrust means, and a ship for measuring the speed of the free-running model ship Speed measuring means and control means for controlling the propeller rotation speed of the propeller and the output of the auxiliary thrust means based on the estimated basic performance of the actual ship and the measured ship speed, and under the external force of the free-running model ship In particular, the control means performs the method of making the propulsion unit-related characteristics of the free-running model ship similar to the actual ship. It is possible to implement an actual ship similarity device that can be used to perform a maneuvering performance test and to estimate and confirm the ship maneuvering characteristics of the actual ship.

Further, the control means, the ship speed of the free sailing model ship previously obtained the free cruising model ship propeller speed and the auxiliary thrust coefficient f _TA by a method of the thruster associated properties actual ship similarity of By storing and controlling the relationship, the maneuvering performance test for estimating and confirming the maneuvering characteristics of the actual ship using the model ship can be performed without calculating the parameters necessary for the control in real time.

  Further, the ship speed measuring means measures the longitudinal speed component of the free-running model ship by using a model ship according to the longitudinal component of the free-running model ship speed. A maneuverability test to estimate and confirm the maneuvering characteristics of the ship can be conducted.

It is a figure which shows the simulation calculation result of the free-running model ship test when propeller rotation speed n _s ' of an actual ship is made constant. It is a figure which shows the simulation calculation result of the free-running model ship test when propeller rotation speed n _s ' of an actual ship is made constant. Is a diagram showing a simulation calculation result of free sailing model ship tests when a constant propeller torque Q _s' of actual ship. Is a diagram showing a simulation calculation result of free sailing model ship tests when a constant propeller torque Q _s' of actual ship. Is a diagram showing a simulation calculation result of free sailing model ship tests when the constant horsepower P _s' of actual ship. Is a diagram showing a simulation calculation result of free sailing model ship tests when the constant horsepower P _s' of actual ship. It is a figure which shows an example of the free-running model ship test apparatus in embodiment of this invention. It is a figure which shows another example of the free-running model ship test apparatus in embodiment of this invention. It is a figure which shows another example of the free-running model ship test apparatus in embodiment of this invention.

[First Embodiment]
<Free-running model ship test method>
In this embodiment, based on the basic performance estimation of the actual ship, the propeller rotational speed and the output of the auxiliary thrust device are controlled based on the measurement data while measuring the longitudinal component u of the ship speed that changes under external force. Thus, the ship speed response of the model ship under external force is similar to that of the actual ship. Under external force, ships generally require steering. Steering induces rudder resistance and tilt / turning resistance, so these resistance components must be similar between the model ship and the actual ship in order to make the ship speed response similar.

ここで、水の密度ρ、船の長さＬ、重力加速度ｇを用いて、質量はρＬ^３、速度は√（ｇ／Ｌ）、力はｒＬ^３ｇ、時間は√（Ｌ／ｇ）によって無次元化を行っている。また、無次元値を’（ダッシュ）をつけて表す。変数の上の点は無次元時間に関する微分を表す。水の密度ρと船の長さＬについては実船と模型船それぞれに対応する値を用いる。 The movement of the ship in the front-rear direction under external force is expressed by Equation (13).

Here, using the density ρ of water, the length L of the ship, and the acceleration of gravity g, the mass is ρL ³ , the speed is √ (g / L), the force is rL ³ g, and the time is √ (L / g). It is dimensionless. In addition, dimensionless values are indicated with a '(dash). The point above the variable represents the derivative with respect to dimensionless time. As the water density ρ and the ship length L, values corresponding to the actual ship and the model ship are used.

Also, m denotes the mass of the ship, m _x is the longitudinal direction of the additional mass due to the back and forth swinging of the ship, respectively. u is the longitudinal component of the ship speed (hereinafter referred to as “ship speed” unless otherwise specified), t is the thrust reduction rate, T is the propeller propulsion force, R is the resistance of the ship when traveling straight water, E is the wave and wind External force F, F represents resistance due to steering, tilting and turning.

  Consider separately whether the hull motion of the encounter cycle with waves and the circular motion of water particles due to waves affect the self-propulsion factors such as the wake coefficient and the effective inflow velocity of propellers can be ignored as high-frequency components.

  Further, the effects of the left-right component v ′ of the ship speed and the dimensionless turning angular velocity r ′, which will be described later, on the self-propulsion factors such as the wake coefficient are not direct, but these are not directly related to the ship speed u ′ and the propeller load degree described later. Suppose that it can be considered through the effects on

ここで、ｎ’は次式で表される無次元プロペラ回転数である。

さらに、無次元化された船の平水中直進時の抵抗Ｒ’は次のような関数型と考えられる。

ここで、Ｒ_ｎは水を対象としたレイノルズ数、ｕ’は無次元船速を示す。無次元化の定義によりｕ’は船速の前後方向成分を代表船速としたフルード数と同義である。 Considering the above, the dimensionless propeller thrust T ′ can be regarded as the following function type.

Here, n ′ is a dimensionless propeller rotational speed represented by the following equation.

Furthermore, the resistance R ′ of the dimensionless ship when it goes straight in the flat water is considered to be the following function type.

Here, R _n represents the Reynolds number for water, and u ′ represents the dimensionless ship speed. By the definition of non-dimensionalization, u ′ is synonymous with the fluid number in which the longitudinal component of the ship speed is the representative ship speed.

ここで、Ｗ_ａは船と波との出会角と波長船長比、波振幅船長比に代表される波に関する条件を示す。Ｗ_ｉは風向と無次元風速に代表される風に関する条件を示す。Ｗ_ｉとＷ_ａはフルードの相似則に基づいて決められる。 Further, the external force E ′ caused by the non-dimensionalized wave and wind can be regarded as the following function type.

Here, W _a indicates a condition relating to a wave represented by an encounter angle between _a ship and a wave, a wavelength ship length ratio, and a wave amplitude ship length ratio. W _i indicates the conditions for the wind, which is represented by the wind direction and the non-dimensional wind speed. W _i and W _a are determined based on Froude's similarity law.

  In the present embodiment, the non-dimensionalized wave and wind external force E ′ representing the influence of the wave and the wind considers only the low frequency component that fluctuates slowly ignoring the high frequency component of the encounter frequency with the wave. To do. In addition, although the influence of the Reynolds number on the air can be considered in the wind force, in this embodiment, the effect of the Reynolds number of the wind can be ignored by focusing on the phenomenon under the surface of the water. It is not treated as a variable.

The resistance F ′ caused by the non-dimensional steering / tilting / turning includes a centrifugal force component based on the mass of the ship and a fluid force component based on the additional mass. Since these can be set to the same value for the actual ship and the model ship by the geometrical similarity between the actual ship and the model ship as well as the non-dimensionalized ship's mass m ', It becomes an expression.

ここで、δは舵角、ｖ’は船速の左右成分、ｒ’は無次元回頭角速度をそれぞれ示す。 Incidentally, m _y and m ₂₆ denotes a additional mass in the horizontal direction due to the bow swing in the horizontal direction and the ship due to the sway of the ship. Here, F ₀ ′ can be regarded as the following function type.

Here, δ is the rudder angle, v ′ is the left / right component of the ship speed, and r ′ is the dimensionless turning angular velocity.

The dimensionless turning angular velocity r ′ is defined by the following equation.

Meeting angle and wavelength of the representative Condition for W _i and ships and waves regarding wind dimensionless propeller speed n 'the wind direction and the dimensionless wind velocity can be given as the state variables in the model experiments of more variables This is _a condition W _a related to a wave represented by a ship length ratio and a wave amplitude ship length ratio. Here, W _i and W _a can be arbitrarily given according to the sea and sea conditions assumed by the actual ship.

By the way, if the fluctuation component of the external force is small compared to the inertial force of the ship and the response of the ship speed is sufficiently slow, Equation (13) can be handled quasi-steady. Here, the following balance formula is established during steady straight running in plain water where no external force is applied.

  Expression (21) is a relationship that should be established for both a real ship and a model ship, but the Reynolds number differs greatly between the actual ship and the model ship. The resistance R ′ of the converted ship when it goes straight in flat water has different values for the actual ship and the model ship. Since R ′ is different between the model ship and the actual ship, the dimensionless propeller rotational speed n ′ is different between the actual ship and the model ship even if the dimensionless ship speed u ′ is the same.

In plain water, the similarity between the actual ship and the model ship can be ensured by the sum of the second and third terms of equation (13) being zero. However, if the actual ship and model ship under external forces boat speed changes in the environment of the same W _i and W _a, altered with respect to the boat speed and the non-dimensional propeller thrust T 'dimensionless ship Since the resistance R ′ when traveling straight in flat water shows different behavior, the sum of the second term and the third term generally does not become zero under an external force, and generally does not become the same value between an actual ship and a model ship. As a result, the change in ship speed under external force is not similar between the actual ship and the model ship.

  Therefore, a case where an auxiliary thrust device is provided on the model ship will be considered in order to ensure the similarity of ship speed change under external force. Here, the auxiliary thrust device affects the other movements of the ship by a duct type fan, a compressed air blowing device mounted on a free-running model ship, or a towing cart that tracks and runs along a free-running model ship. It includes all mechanisms and devices that can apply force only in the front-rear direction without giving any.

ここで、添字のｓは実船の値を示し、ｍは模型船の値であることを示す。実船と模型船で同じ値に設定できる変数には添字をつけない。 When the equation of motion when the auxiliary thrust T _A 'is applied to the model ship is compared with the equation of motion of the actual ship, the following equation is obtained.

Here, the subscript s indicates the value of the actual ship, and m indicates the value of the model ship. Variables that can be set to the same value on the actual ship and model ship are not subscripted.

Actual ship and model ship boat speed response is similar in the environment of the same W _i and W _a, i.e. dimensionless ship speed u 'to have the same response, dimensionless ship speed u' to changes in It is only necessary that the change on the right side of equation (21) is the same for the actual ship and the model ship.

From equation (17), the following equation holds the same set of W _i and W _a given the same dimensionless ship speed u '.

Further, if the rudder angle δ, the horizontal component v ′ of the ship speed, and the dimensionless turning angular velocity r ′ are the same for the same dimensionless ship speed u ′, the equation (24) is established.

  However, the equation (24) shows that a given dimensionless propeller rotational speed n having a dimensionless ship speed u ′ and a rudder angle δ, a horizontal component v ′ of the ship speed and a dimensionless turning angular speed r ′ of an actual ship and a model ship. It is established when the result becomes the same under the condition of ', etc., and is not given by setting like the condition of the propeller rotation speed and the wind / wave. In order to make the effects of the steering angle δ, the horizontal component v ′ of the ship speed, and the dimensionless turning angular velocity r ′ similar, it is necessary that the steering effects are similar.

The second term on the right side of Equation (21) cannot be made equal between the actual ship and the model ship. Therefore, when the auxiliary thrust is not used, the first term on the right side cannot be made equal. This is the reason why the ship speed response under external force cannot maintain the similarity in the normal free-running model test. In the present embodiment, the auxiliary thrust term T _A ′ can be given by using the auxiliary thrust. Therefore, assuming the similarity in rudder effect, the similarity between the actual ship and the model ship is ensured if Expression (25) holds for an arbitrary dimensionless ship speed u ′.

That is, equation (23) is established by setting the experimental conditions, equation (24) is established by making the steering effect similar, and equation (25) is established by controlling the auxiliary thrust term T _A ′. By doing so, the right side of the equation (22) can behave equally with respect to u ′ in the actual ship and the model ship. As a result, similarity in ship speed response is ensured.

  In the case where the external force is symmetric with respect to the ship, or when both sides of equation (24) are close to 0 due to the small steering angle δ, the horizontal component v ′ of the ship speed, and the dimensionless turning angular velocity r ′, etc. As a special case, the condition for ensuring the similarity of rudder effect can be excluded.

摩擦修正に必要な力Ｔ_ＳＦＣ’は次式で定義される無次元船速ｕ’とレイノルズ数Ｒ_ｎの関数である。

Here, an auxiliary thrust coefficient representing the auxiliary thrust required for friction correction is introduced. Since the auxiliary thrust term T _A ′ can be given arbitrarily, the auxiliary thrust term T _A ′ can be determined by introducing the auxiliary thrust coefficient f _TA and the force T _SFC ′ necessary for so-called friction correction as in the following equation: it can.

Power T _SFC necessary friction modifiers _'is dimensionless ship velocity u, which is defined by the following expression' a function of the Reynolds number R _n and.

Using equation (27), equation (25) can be rewritten into equation (28).

ここで、Ｄ’はプロペラ直径の無次元値を示し、次式で定義される。

If found effective wake rate thrust matching method, _{'dimensionless} propeller thrust T _m of a the model _ship' dimensionless propeller thrust T _s of the actual ship it can be expressed by the following equation using the Propeller characteristics .

Here, D ′ represents a dimensionless value of the propeller diameter and is defined by the following equation.

ここで、ｗは有効伴流率を示す。 K _Ts and K _Tm indicate the propeller independent characteristics of the actual ship and the model ship, and are functions of the propeller advance rate of the actual ship and the model ship, respectively, defined by the following equations.

Here, w represents an effective wake rate.

The thrust reduction coefficient 1-t and the effective wake coefficient 1-w are often handled as functions of the propeller load degree t. Here, the propeller load degree t is defined by the following equation.

J _{H in the} equation (32) represents an apparent advance rate of the ship and is represented by the following equation.

Considering the state of the actual ship to be similar, the shape influence coefficient of the target ship, the equivalent plate friction resistance coefficient, the wave resistance coefficient, the thrust reduction coefficient 1-t, the effective wake coefficient 1-w, the propeller single characteristics These scale effects are known, including their presence or absence. The state of the actual ship according to the change in the dimensionless ship speed u ′ differs depending on the dimensionless prober rotation speed n _s ′ of the actual ship.

The dimensionless prober rotation speed n _s ′ can be estimated under conditions such as constant propeller rotation speed, constant propeller torque, and constant horsepower. That is, the combination of the dimensionless ship speed u ′ that satisfies the formula (21), the dimensionless prober rotation speed n _s ′ of the actual ship, the propeller torque, and the horsepower when the standard level water is satisfied. The change of the state quantity when the ship speed changes according to either is estimated. Any one of the estimated values is used as a constraint condition in a method of making a ship speed change similar to that described later.

  Note that a method considering engine characteristics may be used for estimating the actual ship state. However, as described above, it is preferable to consider only the low-frequency component that slowly changes while ignoring the high-frequency component that changes in the encounter period with the wave.

  Hereinafter, a method of making the ship speed change similar between an actual ship and a model ship under external force will be described.

There are two unknowns in the equation (28): the dimensionless propeller rotation speed n _m ′ of the model ship and the auxiliary thrust coefficient f _TA . The constraint condition is similar to the steering effect for satisfying the equation (24). When solving the equation (25) using the steering effect similarity (u _Rm '= u _Rs ') for satisfying the equation (24) as a constraint, the unknown dimensionless propeller rotation number _nm and the auxiliary thrust coefficient f _TA is uniquely determined. Here, u _Rm ′ is a dimensionless longitudinal component of the rudder effective inflow speed of the model ship, and u _Rs ′ is a dimensionless longitudinal component of the rudder effective inflow speed of the actual ship.

On the other hand, when the similarity of rudder effectiveness is secured by another method such as correction of rudder angle or correction of rudder area, or when similarity of rudder effectiveness is not a constraint condition for reasons such as symmetry as described above, Since there are two unknowns for 25), there are innumerable combinations of solutions. There can be either a solution that does not use the auxiliary thrust with the auxiliary thrust coefficient _fTA being 0, or a solution that does not use the propeller with the dimensionless propeller thrust _Tm ′ of the model ship being 0. In addition, when ensuring the effectiveness of the rudder by correcting the rudder angle or by revising the rudder area, the correction or correction corresponding to the combination of the dimensionless propeller rotational speed n _m ′ and the auxiliary thrust coefficient f _TA satisfying equation (25) is necessary. In the following, several methods are proposed in consideration of the practicality of experiments using model ships.

(1) Method for Similarity of Ship Speed Change and Propeller Propulsion Force In the first method, not only similarity of ship speed change but also similarity of propeller thrust force is ensured. This method is suitable for a model experiment for examining changes in propeller propulsion force under external force and phenomena related thereto.

Similarity of propeller propulsion force is expressed by equation (34).

At this time, Expression (35) is derived from Expression (29).

When the dimensionless ship speed u ′ is the same value for the actual ship and the model ship, Expression (36) is obtained by considering Expression (32) and Expression (33).

That is, the similarity of the propeller propulsion force means that the propeller load degree is equal between the actual ship and the model ship. Furthermore, if the thrust reduction coefficient 1-t is a function of the propeller load degree t or the dimensionless ship speed u ′, Expression (37) is established.

Comparing equation (37) and equation (28), the similarity of the propeller thrust is equivalent to equation (38).

At this time, the relationship of the equation (39) is obtained from the equation (26).

That is, it can be seen that the similarity of propeller thrust is obtained by so-called friction correction. In order to make the propeller propulsive force similar between the actual ship and the model ship, the auxiliary thrust coefficient f _{TA is set} to 1 and the dimensionless propeller rotation speed n _m ′ of the model ship is set to the dimensionless ship speed u ′ according to Equation (25). It can be obtained as a function of.

(2) Method for Similarizing Ship Speed Change and Propeller Torque In the second method, not only similarity of ship speed change but also similarity of propeller torque is ensured. This method is suitable for a model experiment for examining a change in propeller torque under an external force and a phenomenon related thereto, in particular, a load applied to the main engine when a ship speed changes under an external force.

ここで、Ｑはプロペラトルクを表し、その無次化にはρＬ^４ｇを用いる。有効伴流係数を推力一致法で求めた場合、プロペラトルクＱの無次元値はプロペラ単独性能を用いて式（４１）で表現される。

ここで、上式でＫ_Ｑはトルクに関するプロペラ単独性能、η_Ｒはプロペラ船後効率比を示す。 The similarity between the propeller torque of the actual ship and the model ship is given by equation (40).

Here, Q represents the propeller torque, and ρL ⁴ g is used for demagnetization. When the effective wake coefficient is obtained by the thrust matching method, the dimensionless value of the propeller torque Q is expressed by equation (41) using the propeller single performance.

Here, in the above equation, K _Q is the propeller independent performance related to torque, and η _R is the propeller ship efficiency ratio.

In this method, the dimensionless propeller rotation speed n _m ′ of the model ship is obtained using Expression (40) as a constraint condition, and the corresponding auxiliary thrust coefficient f _TA is obtained based on Expression (25) to obtain the absence of the model ship. The dimensional propeller rotation speed n _m ′ and the auxiliary thrust coefficient f _TA can be obtained as a function of the dimensionless ship speed u ′.

(3) Method of Similarizing Ship Speed Change and Propeller Rotation Speed In the third method, not only the similarity of ship speed change but also the propeller rotation speed is secured between the actual ship and the model ship. In this case, as shown in the equation (42), the apparent advance rate is also equal between the actual ship and the model ship.

In this method, the dimensionless propeller rotation speed n _m ′ of the model ship is determined based on the equation (43), and then the corresponding auxiliary thrust coefficient f _TA is obtained based on the equation (25). The dimensionless propeller rotation speed n _m ′ and the auxiliary thrust coefficient f _TA of the ship can be obtained as functions of the dimensionless ship speed u ′.

(4) Method of Similarizing Ship Speed Change and Horsepower In the fourth method, not only the similarity of ship speed change but also the similarity of horsepower is ensured. It is suitable for model experiments to investigate changes in horsepower under external force and related phenomena, especially main engine horsepower when ship speed changes under external force.

The similarity of horsepower is given by equation (44).

In this method, after obtaining the dimensionless propeller rotation speed n _m ′ of the model ship using Expression (44) as a constraint, the model ship is obtained by obtaining the corresponding auxiliary thrust coefficient f _TA based on Expression (25). The dimensionless propeller rotation speed n _m ′ and the auxiliary thrust coefficient f _TA can be obtained as a function of the dimensionless ship speed u ′.

(5) Method of matching the propeller slip ratio with the similarity of the ship speed change In the fifth method, not only the similarity of the ship speed change but also the propeller slip ratio is set to the same value for the actual ship and the model ship. At this time, the propeller forward rate is also the same for the actual ship and the model ship. Although it is in different wakes, the operating state of the propeller can be made similar, so it is suitable for model experiments to investigate the propeller characteristics when the ship speed changes under external force.

Propeller slip ratio _s s of actual ship and model ship, _{s m} is represented by the formula (45).

The coincidence between the propeller slip ratios s _s and s _m is nothing but the coincidence between the propeller advance rates J _s and J _m , as shown in the equation (45).

In this method, after obtaining the dimensionless propeller rotation speed n _m ′ of the model ship using Expression (46) as a constraint, the model ship is obtained by obtaining the corresponding auxiliary thrust coefficient f _TA based on Expression (25). The dimensionless propeller rotation speed n _m ′ and the auxiliary thrust coefficient f _TA can be obtained as a function of the dimensionless ship speed u ′.

Equation (46) is equivalent to equation (47).

<Calculation example>
Hereinafter, an example of calculation when the target actual ship is KVLCC1 (flat water standard ship speed 15.5 kt) and the model ship is a scale model of an actual ship 1/110 will be described. The items to be calculated are the dimensionless propeller rotation speed n _m ′ of the model ship and the auxiliary thrust coefficient _fTA for setting the ship speed change similar to that of the actual ship, and the dimensionless effective inflow speed of the model ship. _{Changes in the} longitudinal speed component u _Rm ′, propeller slip ratio s _m , dimensionless auxiliary thrust T _A ′, dimensionless propeller thrust T _m ′, dimensionless propeller torque Q _m ′, dimensionless horsepower P _m ′ with respect to ship speed It was.

The state of the actual ship that should be similar is one of the three states in which the propeller rotational speed n _s ′, the propeller torque Q ′, and the horsepower P ′ are constant. The model ship is in the same state as the ship speed u ′ and at the same time the dimensionless longitudinal component (rudder effect) u _Rm ′ of the rudder effective inflow speed, propeller propulsion force T _m ′, propeller torque Q _m ′, horsepower P _m ', Propeller slip ratio s _m , propeller rotation speed n _m ' is used to control the actual ship rudder effect u _Rs ', propeller propulsion force T _s ', propeller torque Q _s ', horsepower P _s ', propeller slip ratio s _s The speed change was made similar to the actual ship without the auxiliary thrust (w / oAT) in a state similar to the propeller rotational speed n _s ′.

In the coefficient used for the calculation, the resistance in plain water was determined by a three-dimensional extrapolation method. Scale effect and roughness correction were based on the ITTC method. In addition, the scale effect of the propeller independent characteristics K _T and K _Q and the effective wake coefficient 1-w of the actual ship and the model ship was determined by the ITTC method. Further, the shape influence coefficient, the wave resistance coefficient, the thrust reduction coefficient 1-t, the propeller ship efficiency ratio η _R , the ratio ε between the rudder position wake coefficient and the propeller position wake coefficient, and the propeller wake acceleration rate The scale effect is not considered in the coefficient κ. Further, it is assumed that the efficiency ratio η _R after the propeller ship is 1.0. Further, the effective wake coefficient 1-w and the thrust reduction coefficient 1-t are constant values regardless of the ship speed and the propeller load.

FIG. 1 shows that the propeller rotation speed n _s ′ of the actual ship is constant, and the longitudinal component u _Rm ′ of the rudder effective inflow speed of the model ship, propeller thrust T _m ′, propeller torque Q _m ′, and horsepower P _m ′ The calculation results when one of them is made to be similar to the longitudinal component u _Rs ', propeller thrust T _s ', propeller torque Q _s ', and horsepower P _s ' of the rudder effective inflow speed of the actual ship are shown. The calculation results indicate changes in each item when the ship speed (ratio between the dimensionless ship speed u ′ and the flat water ship speed u ₀ ′) is changed.

Figure 2 is a propeller speed n _s in actual _ships' was constant, dimensionless longitudinal direction component of the rudder effective inflow velocity of the model ship u _Rm ', one of the propeller slip ratio s _m and propeller speed n _m' The calculation results are shown in a state similar to the dimensionless longitudinal component u _Rs ′, propeller slip ratio s _s, and propeller speed n _s ′ of the effective inflow velocity of the actual ship. The calculation results are also shown at the same time when no given auxiliary thrust _{T A} (w / _oAT). The calculation result indicates changes in each item when the ship speed (the dimensionless ship speed u ′ is changed to the flat water ship speed u ₀ ′).

FIG. 3 shows that the propeller torque Q _s ′ of the actual ship is constant, and any of the longitudinal component u _Rm ′ of the rudder effective inflow speed of the model ship, propeller thrust T _m ′, propeller torque Q _m ′, and horsepower P _m ′ The calculation results when K is made similar to the longitudinal component u _Rs ', propeller thrust T _s ', propeller torque Q _s ', and horsepower P _s ' of the rudder effective inflow speed of the actual ship are shown. The calculation result indicates changes in each item when the ship speed (the dimensionless ship speed u ′ is changed to the flat water ship speed u ₀ ′).

FIG. 4 shows that the propeller torque Q _s ′ of the actual ship is constant and any one of the dimensionless longitudinal component u _Rm ′, the propeller slip ratio s _m, and the propeller rotational speed n _m ′ of the model ship's rudder effective inflow speed is _realized. ship rudder effective inflow velocity of the dimensionless longitudinal direction component u _Rs shows the calculation results when the state of the similar to the 'propeller slip ratio s _s and propeller speed n _s'. The calculation results are also shown at the same time when no given auxiliary thrust _{T A} (w / _oAT). The calculation result indicates changes in each item when the ship speed (the dimensionless ship speed u ′ is changed to the flat water ship speed u ₀ ′).

FIG. 5 shows that the horsepower P _s ′ of the actual ship is constant, and any one of the longitudinal component u _Rm ′, propeller thrust T _m ′, propeller torque Q _m ′, and horse power P _m ′ of the effective inflow speed of the model ship. _Shows the calculation results when the engine is made similar to the longitudinal component u _Rs ', propeller propulsion force T _s ', propeller torque Q _s ', and horsepower P _s ' of the rudder effective inflow speed of the actual ship. The calculation result indicates changes in each item when the ship speed (the dimensionless ship speed u ′ is changed to the flat water ship speed u ₀ ′).

FIG. 6 shows that the actual ship's horsepower P _s ′ is constant, and any one of the dimensionless longitudinal component u _Rm ′, propeller slip ratio s _m, and propeller rotation speed n _m ′ of the rudder effective inflow speed of the model ship is The calculation results are shown in a state similar to the dimensionless longitudinal component u _Rs ′, the propeller slip ratio s _s, and the propeller rotational speed n _s ′ of the rudder effective inflow speed. The calculation results are also shown at the same time when no given auxiliary thrust _{T A} (w / _oAT). The calculation result indicates changes in each item when the ship speed (the dimensionless ship speed u ′ is changed to the flat water ship speed u ₀ ′).

<Proportioner-related characteristics of a free-running model ship>
FIG. 7 is a diagram showing a free-running model ship test apparatus 100 for realizing the free-running model ship test method according to the embodiment of the present invention.

  As shown in FIG. 7, the free-running model ship test apparatus 100 includes an analog / pulse converter 12, a motor amplifier 14, a duct fan motor 16 and a dynamometer 18 mounted on the free-running model ship 10, and an automatic A camera 22 mounted on the tracking carriage 20, a force meter amplifier 24, a control computer (control PC) 26, a propeller 28, and a propeller drive unit 30 are configured.

  The free-running model ship 10 is a model ship imitating an actual ship to be tested. The free-running model ship 10 has a main thrust system such as a propeller 28 in addition to the auxiliary thrust system described below, and is configured to be able to freely travel on the water. The propeller drive unit 30 includes a motor for driving the propeller 28 that is the main drive system of the free-running model ship 10. The propeller drive unit 30 is preferably a motor that can control the rotation speed, such as a servo motor.

  The automatic tracking cart 20 is configured to image the free-running model ship 10 with a camera 22 and automatically track the free-running model ship 10 under the control of the control computer 26 based on the information. For example, the automatic tracking cart 20 is attached to a rail disposed on the test pool, and is configured to track the free-running model ship 10 by traveling on the rail. Further, the speed (ship speed) of the free-running model ship 10 is measured by tracking the automatic tracking carriage 20 and input to the control computer 26.

  By tracking the automatic tracking carriage 20, the speed (ship speed) of the free-running model ship 10 is measured and input to the control computer 26. In the control computer 26, the auxiliary thrust and the propeller rotational speed are set based on the test conditions and the speed of the free-running model ship 10, and the auxiliary thrust command signal and the propeller rotational speed command corresponding to the set auxiliary thrust and the propeller rotational speed are set. A signal is generated. The auxiliary thrust command signal is input to the duct fan motor 16 via the analog / pulse converter 12 and the motor amplifier 14, and the duct fan motor 16 is driven. Thus, a desired auxiliary thrust is given to the free-running model ship 10 by the duct fan motor 16. Further, the propeller rotational speed command signal is input to the propeller driving unit 30, thereby controlling the rotational speed of the propeller 28.

  Specifically, a duct fan motor 16 is mounted as auxiliary thrust adding means. The duct fan motor 16 is controlled in output based on the auxiliary thrust command signal input to the analog / pulse converter 12, and the output is an auxiliary thrust provided separately from the main thrust system of the free-running model ship 10. Become. When an auxiliary thrust command signal is input to the analog / pulse converter 12, it is converted into a pulse signal for controlling the duct fan motor 16 so as to generate a thrust according to the signal, and the pulse signal is amplified by the motor amplifier 14. Input to the duct fan motor 16 causes the duct fan motor 16 to be driven. Thus, a desired auxiliary thrust is given to the free-running model ship 10 by the duct fan motor 16.

  The free-running model ship 10 is equipped with a dynamometer 18 that detects and outputs the output of the duct fan motor 16. The dynamometer 18 detects the auxiliary output of the duct fan motor 16 and outputs it to the galvanometer amplifier 24.

  A dynamometer amplifier 24 is mounted on the automatic tracking carriage 20 and an actual auxiliary output detected by the dynamometer 18 is input. The dynamometer amplifier 24 amplifies the actual auxiliary output and outputs it to the control PC 26. The control PC 26 receives a signal corresponding to the auxiliary output from the galvanometer amplifier 24, generates an auxiliary thrust command signal so that the auxiliary output becomes a desired value, and outputs the auxiliary thrust command signal to the analog / pulse converter 12. Thus, by performing feedback control, a desired auxiliary thrust can be applied to the free-running model ship 10.

  Moreover, it is good also as a structure like the free-running model ship test apparatus 102 shown in FIG. In the free-running model ship test apparatus 102, the galvanometer amplifier 24 and the control computer (control PC) 26 are also mounted on the free-running model ship 10. In addition, about the same structure as the free-running model ship test apparatus 100, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the free-running model ship test apparatus 102, a ship speed detector 32 is further mounted on the free-running model ship 10. The ship speed detector 32 measures the speed (ship speed) of the free-running model ship 10 and inputs it to the control computer 26. For example, the ship speed detector 32 may obtain the ship speed from speed measuring means such as a Pitot tube, or from the temporal change in the position of the free-running model ship 10 obtained from position measuring means such as GPS. You may seek speed. Further, the speed of the watercraft may be obtained using an electromagnetic LOG sensor, a Doppler LOG sensor, or the like.

  Moreover, it is good also as a structure like the free-running model ship test apparatus 104 shown in FIG. In the free-running model ship test apparatus 104, a ship speed information receiver 34 is mounted on the free-running model ship 10 instead of the ship speed detector 32. The ship speed information receiver 34 receives ship speed information of the free-running model ship 10 from a ship speed detector 36 provided on land, and inputs the information to the control computer 26. The boat speed detector 36 may obtain the boat speed of the free-running model ship 10 by, for example, an optical method or a method using radio. Further, the ship speed may be obtained from a temporal change in the position of the free-running model ship 10 obtained from a position measuring means such as GPS.

  In the free-running model ship test apparatuses 102 and 104, the free-running model ship 10 may be equipped with a power source such as a battery, and the power necessary for the test may be supplied from the power source. As a result, the test can be performed on the free-running model ship 10 alone without supplying external power from the automatic tracking cart 20 or the like.

[Second Embodiment]
In the first embodiment, only the case where the propeller rotational speed of the actual ship is normal rotation is targeted. However, the same idea can be applied to estimation of stopping performance by propeller reverse rotation. In fact, in the reverse rotation stop test stipulated in the IMO maneuverability standard, it is assumed that the rudder is held at the center when the reverse rotation is stopped, and it is known that the rudder is generally not effective when the propeller is reversed.

  The following shows how to control the auxiliary thrust and the model propeller speed when performing a reverse rotation stop test on a free-running model ship under disturbance in addition to the normal water specified by the IMO maneuverability standard. .

  During the forward run and during the forward rotation of the propeller after the reverse stop issuance, the calculation is performed based on the first embodiment. When the speed of the propeller is reversed, the rudder force is assumed to be 0, and calculation is performed until the ship speed reaches 0, considering the longitudinal force, left-right force, and turning moment components of the unbalanced force due to the reverse rotation of the propeller. This is a basic calculation procedure.

The unbalance force during propeller reversal is organized as a function of the ship's apparent forward rate _JH . The apparent advance rate _JH of the ship is defined by Expression (48).

The apparent advance rate _JH of the ship is represented by the forward / backward component u of the ship speed, the propeller rotation speed n, and the propeller diameter D, but the propeller rotation speed n takes a negative value when the propeller reverse rotation is considered. At present, the estimation of the unbalanced force at the time of propeller reverse rotation stop is only possible by model experiments.

It is considered that the unbalance force at the time of propeller reversal in the theoretical calculation is generally given as a function of the ship's apparent advance rate _JH . When considering the reverse stop performance of a specific ship only by a model scale, there is no problem by giving the force at the time of reverse rotation as a function of the ship's apparent forward rate _JH . The unbalance force during the reversal of the propeller may be regarded as a function of a variable in which the propeller diameter D in the equation (48) is replaced with the propeller pitch instead of the apparent advance rate _JH of the ship. There is no difference.

Here, considering the scale effect at the time of propeller reversal, according to the above theoretical calculation, the hull motion at the time of reverse rotation stop is governed by the unbalanced force at the time of propeller reversal. Dominated by _H. In addition, when considering the force at the time of propeller reversal, the flow field around the propeller is considered to have a dominant influence, so when considering the scale effect of the actual ship and the model ship, these forces are the apparent advance of the ship. We consider it more appropriate to consider it as a function of propeller advance rate J rather than rate _JH . Here, the propeller advance rate J is defined by equation (49).

ここで、Ｐはプロペラピッチを示す。 Scale effects appear in the wake coefficient 1-w. Based on the above idea, in order to discuss the scale effect on reverse stop performance, the unbalance force at the time of reverse rotation of the propeller is regarded as a function of the propeller advance rate J. In addition, regarding it as a function of the propeller advance rate J is equivalent to regarding it as a function of the propeller slip s. The propeller slip s is defined by the formula (50).

Here, P represents a propeller pitch.

  When considering the similarity law at the time of reverse stop, we consider simultaneous equations to be solved for model ship control. Hereinafter, also in the second embodiment, a dimensionless value is indicated with a dash '. Variables that have different dimensionless values between the model ship and the actual ship are given m and s as subscripts, respectively. Variables that have the same dimensionless value are not marked with m or s.

Since the rudder is effective during normal rotation of the propeller, it is generally necessary to resemble the rudder effect. In case of disturbance, it is essential to adjust the rudder speed. The rudder effect boat speed correction is expressed by equation (51).

Equation (51) is an equation to be solved in order to obtain the auxiliary thrust coefficient f _TA for controlling the model ship during the forward rotation of the propeller and the propeller rotation speed n _m ′ of the model ship. However, there is a special case during normal rotation of the propeller during normal water. When running in flat water, the vehicle is running straight, and according to the IMO maneuverability standard, the rudder angle is 0 even after the reverse stop command is issued. Even if it is an actual ship self-propelled point or other than that, for example, even if the propeller rotation speed n is such that the propeller advance rate J is matched between the model ship and the actual ship, there is no problem as long as the ship speed is similar.

  When the propeller enters reverse rotation, the propeller advance rate J of the model ship is set to the same value as the actual ship so that the unbalanced force at the time of reverse rotation of the propeller becomes similar. By matching the propeller advance rate J, the unbalance force at the time of reversing the propeller becomes similar, the hull motion induced by this becomes similar, the disturbance force becomes similar, and the resulting hull motion becomes similar.

The propeller advance rates J _m and J _s of the model ship and the actual ship are expressed by Expression (52) and Expression (53).

The coincidence of the propeller advance rate J and the similarity of the advance speed are expressed by the following simultaneous equations.

Expression (52) and Expression (53) to Expression (54) are equivalent to the following expression.

ここで、ｎ_０ｓ’は助走時のプロペラ回転数、ｎ_ｒｓ’は指令逆転回転数を示す。指令逆転回転数ｎ_ｒｓ’は負の値である。時刻０がプロペラ逆転発令時刻、ｔ_１’はプロペラ回転数が０となる時刻、ｔ_２’はプロペラ回転数が指令逆転回転数に達する時刻を示す。ｕ’の初期値ｕ_０ｓ’は、助走時のプロペラ回転数ｎ_０ｓ’に対応した値として与えられる。逆転発令後のｕ’は、自由航走模型船の船速ｕ’として時々刻々計測される。 Expression (54) or Expression (55) is a simultaneous equation to be solved in order to obtain the auxiliary thrust coefficient f _TA and the model propeller rotational speed n _m ′ for controlling the model ship during the propeller reversal. In order to solve the equation (54) or the equation (55), it is first necessary to give the propeller rotational speed n _s ′ of the actual ship. The propeller rotation speed n _s ′ of the actual ship is given as a function of time, for example, as shown in Expression (56) regardless of the ship speed.

Here, n _0s ′ indicates the propeller rotation speed during the run-up, and n _rs ′ indicates the command reverse rotation speed. The command reverse rotation speed n _rs ′ is a negative value. Time 0 is the propeller reverse rotation issuing time, t ₁ ′ is the time when the propeller rotational speed is 0, and t ₂ ′ is the time when the propeller rotational speed reaches the command reverse rotational speed. The initial value u _0s ′ of u ′ is given as a value corresponding to the propeller rotation speed n _0s ′ at the time of running. U ′ after the reverse rotation is measured from time to time as the ship speed u ′ of the free-running model ship.

Subject to 'Funesoku u and' propeller speed _{n s} of actual ship, 'until solving the equation (51), the time _{t 1'} after time _{t 1} is solved equation (54) or formula (55) The model ship may be controlled by obtaining the propeller rotation speed n _m ′ and the auxiliary thrust coefficient f _TA of the model ship every moment.

  According to the present embodiment, it is possible to realize a free-running model test that takes into account the influence of external forces such as wind and waves. As a result, the basic performance of the actual ship can be estimated by a free-running model test even under external force.

  The method of making the propulsion unit related characteristics of the free-running model ship in the present invention similar to the actual ship and the propulsion unit-related characteristics of the free-running model ship receive resistance from not only the ship but also external force and fluid. It can be applied to the test of the motion performance of a self-running object. For example, the present invention can be applied to a free running test using various models such as a floating body other than a ship and an underwater navigation body.

  10 Free-running model ship, 16 Duct fan motor, 18 Force meter, 20 Automatic tracking cart, 26 Control computer, 28 propeller, 30 Propeller drive unit, 32 Ship speed detector, 34 Ship speed information receiver, 36 Ship speed Detector, 100, 102, 104 Free-running model ship test equipment.

Claims (17)

  Based on the basic performance estimation of the actual ship, the ship speed that changes under the external force of the free-running model ship is measured, and based on the measured ship speed, the propeller rotational speed of the free-running model ship and the auxiliary thrust means A method for controlling a propulsion device-related characteristic of a free-running model ship by controlling an output and making the propulsion-related characteristic under the external force of the free-running model ship similar to the actual ship. The propeller rotation speed of the free-running model ship and the output of the auxiliary thrust means,

t _s: actual ship thrust reduction rate T's: propeller propulsion of the actual ship (dimensionless value, a function of the propeller speed and boat speed)
t _m : Thrust reduction rate of a free-running model ship T ' _m : Propeller propulsion force of a free-running model ship (dimension value, function of propeller rotation speed and ship speed)
f _TA : Auxiliary thrust coefficient T ' _SFC : Force required for friction correction (dimension value, function of ship speed)
The propulsion device-related characteristics of the free-running model ship according to claim 1, wherein the propulsion-related characteristics of the free-running model ship are controlled based on the propeller rotational speed and the auxiliary thrust coefficient f _TA of the free-running model ship derived based on How to make it similar.   The free flight according to claim 2, wherein the basic performance estimation of the actual ship includes any propeller speed change including constant propeller speed, constant propeller torque, constant propeller output, or reverse rotation. A method to make the propulsion unit-related characteristics of a running model ship similar to an actual ship.   In the case where the similarity of steering / slope navigation / turning resistance is not necessary or separately secured, the free navigation is considered in consideration of the similarity of propeller propulsion force under the external force of the actual ship and the free-running model ship. 4. The method of making the propulsion unit related characteristics of a free-running model ship similar to an actual ship according to claim 2 or 3, wherein a similarity in ship speed response of the traveling model ship is secured.

Ts': Propeller propulsive force of actual ship (dimensionless value, propeller rotation speed and ship speed function)
T _m ' : Propeller propulsion force of a free-running model ship (dimension value, function of propeller rotation speed and ship speed)
5. The propeller rotational speed of the free-running model ship is determined and controlled with the auxiliary thrust coefficient _{fTA set} to 1 in order to ensure similarity of the propeller thrust expressed by To make the propulsion unit-related characteristics of a free-running model ship similar to an actual ship.   When similarity of steering / slope navigation / turning resistance is not required, or when similarity of steering / slope navigation / turning resistance is secured separately, the propeller torque under the external force of the actual ship and the free-running model ship is 4. The propulsion-related characteristics of a free-running model ship according to claim 2 or 3, wherein the similarity in ship speed response of the free-running model ship is secured based on the similarity. How to make. Formula (1),

Q _S ': Propeller torque of actual ship (dimensionless value, function of propeller rotation speed and ship speed)
Q _m ': Propeller torque of a free-running model ship (dimensionless value, function of propeller rotation speed and ship speed)
The propeller-related characteristics of the free-running model ship according to claim 6, wherein the propulsion speed of the free-running model ship and the auxiliary thrust coefficient f _TA are obtained and controlled by combining the How to make a ship similar.   Propeller rotation speed under the external force of the actual ship and the free-running model ship when similarity of steering / slope navigation / turning resistance is not required or when similarity of steering / slope navigation / turning resistance is secured separately 4. The propulsion device-related characteristics of the free-running model ship according to claim 2 or 3, wherein the similarity in ship speed response of the free-running model ship is secured based on the similarity of How to make it similar. Formula (1),

_ns ': Propeller rotation speed of actual ship (dimensionless value)
n _m ': Propeller rotation speed of a free-running model ship (dimensionless value)
9. The propeller-related characteristics of the free-running model ship according to claim 8, wherein the propulsion speed of the free-running model ship and the auxiliary thrust coefficient _fTA are obtained and controlled by combining the How to make a ship similar.   Similarity of horsepower under the external force of the actual ship and the free-running model ship when similarity of steering / slope navigation / turning resistance is not required or when similarity of steering / slope navigation / turning resistance is secured separately 4. The propulsion device-related characteristics of the free-running model ship according to claim 2 or 3, wherein the similarity in ship speed response of the free-running model ship is secured based on the characteristics. how to. Formula (1),

n _s ': Propeller rotation speed of actual ship (dimensionless value)
Q _S ': Propeller torque of actual ship (dimensionless value, function of propeller rotation speed and ship speed)
n _m ': Propeller rotation speed of a free-running model ship (dimensionless value)
Q _m ': Propeller torque of a free-running model ship (dimensionless value, function of propeller rotation speed and ship speed)
11. The propulsion device-related characteristics of the free-running model ship according to claim 10, wherein the propulsion speed of the free-running model ship and the auxiliary thrust coefficient _fTA are obtained and controlled by combining the How to make a ship similar.   Propeller slip ratio under the external force of the actual ship and the free-running model ship when similarity of steering / slope navigation / turning resistance is not required or when similarity of steering / slope navigation / turning resistance is secured separately 4. The similarities of the speed response of the free-running model ship are ensured by matching the propulsion unit-related characteristics of the free-running model ship according to claim 2 or 3, how to. Formula (1),

S _s : Propeller slip ratio of actual ship (propeller speed and ship speed function)
S _m : Propeller slip ratio of a free-running model ship (function of propeller rotation speed and ship speed)
The propulsion device-related characteristics of the free-running model ship according to claim 12, wherein the propulsion speed of the free-running model ship and the auxiliary thrust coefficient _fTA are obtained and controlled by combining the How to make a ship similar.   A free-running model ship having a propeller and auxiliary thrust means, a ship speed measuring means for measuring the speed of the free-running model ship, the basic performance estimation of the actual ship and the propeller based on the measured ship speed And a propulsion unit-related characteristic under the external force of the free-running model ship, which is similar to that of the actual ship. Ship propulsion-related characteristics   The said control means performed the method of making the propulsion apparatus related characteristic of the free-running model ship of any one of Claims 1-13 similar to a real ship, The 14th aspect is characterized by the above-mentioned. Propeller-related characteristics of a free-running model ship. The propeller rotation of the free-running model ship obtained in advance by the method for making the propulsion unit-related characteristics of the free-running model ship similar to an actual ship according to any one of claims 2 to 13 The propulsion unit-related characteristics actual ship similarity device of a free-running model ship according to claim 14, wherein the relation between the number of the auxiliary thrust coefficient f _{TA and} the ship speed is stored and controlled. The propulsion of the free-running model ship according to any one of claims 14 to 16, wherein the ship speed measuring means measures a longitudinal component of a ship speed of the free-running model ship. Equipment related characteristics

Images