KR20120121999A - method of seeding particle into towing tank effectively using CFD in application of particle image velocimetry - Google Patents

method of seeding particle into towing tank effectively using CFD in application of particle image velocimetry Download PDF

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KR20120121999A
KR20120121999A KR1020110039941A KR20110039941A KR20120121999A KR 20120121999 A KR20120121999 A KR 20120121999A KR 1020110039941 A KR1020110039941 A KR 1020110039941A KR 20110039941 A KR20110039941 A KR 20110039941A KR 20120121999 A KR20120121999 A KR 20120121999A
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South Korea
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flow
measurement
particles
particle
upstream point
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KR1020110039941A
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Korean (ko)
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반석호
김진
안해성
이영연
김충만
황승현
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한국해양연구원
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M10/00—Hydrodynamic testing; Arrangements in or on ship-testing tanks or water tunnels
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M99/00—Subject matter not provided for in other groups of this subclass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/36—Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
    • G01P5/18—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance
    • G01P5/20—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance using particles entrained by a fluid stream

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Measuring Volume Flow (AREA)

Abstract

PURPOSE: A method for effectively spraying particles within a measurement region through a computational fluid dynamics analysis using a particle image current in a towing tank is provided to save an amount of consumed particles because the particles are needed to spray to an upstream point of a flow not to other points. CONSTITUTION: A method for effectively spraying particles within a measurement region through a computational fluid dynamics analysis using a particle image current in a towing tank is as follows. A flow analysis is performed by using a computational fluid dynamics under a condition same with a flow measurement test condition using a particle image current meter in a towing tank(6). An upstream point(3) of a flow flowing into a measurement region(2) through an assumed fluid flow is grasped. The upstream point is determined as a particle spraying region(4). The upstream point of the flow is a region where moving a flow line passing through the measurement region along the upstream direction. Most of particles existing in the upstream point flow into the inside of the measurement without being distributed to other regions. The particles existing in other regions except for the upstream point nearly flow into the inside of the measurement region. [Reference numerals] (AA) Towing carrier moving direction

Description

예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 시 전산 유체 역학 해석을 통하여 측정 영역 내에 효과적으로 입자를 분사하는 방법{method of seeding particle into towing tank effectively using CFD in application of particle image velocimetry}Method of seeding particle into towing tank effectively using CFD in application of particle image velocimetry in flow measurement experiment using particle image flowmeter in towing tank

본 발명은 예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 시 전산 유체 역학 해석을 통하여 측정 영역 내에 효과적으로 입자를 분사하는 방법에 관한 것이다.The present invention relates to a method of effectively injecting particles into a measurement region through computational fluid dynamics analysis in a flow measurement experiment using a particle image flow meter in a towing tank.

입자영상유속계(particle image velocimetry)는 최근 각광받고 있는 정성적 유동가시화 방법으로, 점측정(point-wise measurement) 방식인 레이저도플러유속계(laser doppler velocimetry), 열선유속계(hot-wire anemometry), 피토튜브(pitot tube)와는 달리 장측정(whole-field measurement) 방식으로 한 번에 유동의 공간구조를 파악할 수 있는 장점이 있다.
Particle image velocimetry is a qualitative flow visualization method that has recently been in the spotlight, such as laser doppler velocimetry, hot-wire anemometry, and pitot tube, which are point-wise measurements. Unlike the (pitot tube), there is an advantage that the spatial structure of the flow can be grasped at a time by whole-field measurement.

입자영상유속계 시스템은 유동장에서 측정하고자 하는 특정 영역을 조명하기 위한 광원, 광원을 산란시키고 유동을 잘 추종하는 특성을 가진 입자, 입자 영상을 촬영하는 한 개 또는 다수 개의 카메라, 촬영된 입자 영상을 저장하고 이미지 프로세싱을 통해 속도장을 얻어내는 해석 프로그램 및 그 해석 프로그램이 구동되는 컴퓨터 등으로 구성된다.
The particle image flowmeter system stores a light source for illuminating a specific area to be measured in a flow field, particles having characteristics of scattering and well following the flow, one or more cameras that capture particle images, and captured particle images. And an analysis program that obtains the velocity field through image processing, and a computer on which the analysis program is run.

입자영상유속계는 유체의 속도를 측정하는 것이 아니라 유동을 잘 추종하는 특징을 가진 입자의 속도를 대신 계측하여 유체장의 속도(속도장)를 측정하는 장비이다. 한편, 예인수조에서는 전체 유체의 양이 방대하여 예인수조 전체에 입자를 한꺼번에 분포시키기가 어려우므로, 보통 측정 영역 근방에만 입자를 분포시키게 된다. 그러므로 입자영상유속계를 이용한 유동 측정 실험 시에는 측정 영역 내에 입자를 충분한 농도로 고르게 분포시키는 것이 측정의 정확도를 높이는 중요한 방안이 된다.The particle image flow meter is a device that measures the speed of a fluid field (velocity field) instead of measuring the velocity of the fluid, instead of measuring the velocity of the particles that follow the flow well. On the other hand, in the towing tank, since the total amount of the fluid is large, it is difficult to distribute the particles all over the towing tank at once, so that the particles are usually distributed only near the measurement area. Therefore, in the flow measurement experiment using the particle image flowmeter, evenly distributing the particles in a sufficient concentration in the measurement region is an important way to increase the accuracy of the measurement.

본 발명은 예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 시 전산 유체 역학 해석을 통하여 측정 영역 내에 효과적으로 입자를 분사하는 방법을 제공하는 것을 목적으로 한다.It is an object of the present invention to provide a method for effectively injecting particles into a measurement region through computational fluid dynamics analysis in a flow measurement experiment using a particle image flow meter in a towing tank.

상기한 목적을 달성하기 위하여 본 발명은,According to an aspect of the present invention,

예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 조건과 동일한 조건으로 전산 유체 역학을 이용하여 유동 해석을 수행하는 단계 및;Performing flow analysis using computational fluid dynamics under the same conditions as the flow measurement experiment conditions using the particle image flow meter in the towing tank;

예측된 유체 흐름을 통해서 측정 영역 내로 유입되는 유동의 상류 지점을 파악하고 이 지점을 입자 분사 영역으로 결정하는 단계;Identifying an upstream point of the flow entering the measurement zone through the predicted fluid flow and determining this point as the particle injection zone;

를 포함하는, 예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 시 전산 유체 역학 해석을 통하여 측정 영역 내에 효과적으로 입자를 분사하는 방법을 제공한다.In the flow measurement experiment using a particle image flow meter in a towing tank, including a, through the computational fluid dynamics analysis provides a method for effectively injecting particles in the measurement area.

본 발명에 따르면 예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 시 소비되는 입자의 양을 절약할 수 있으며, 변화하는 실험 조건에 대응하여 측정 영역 내의 입자 농도를 용이하게 조절할 수 있다.According to the present invention, it is possible to save the amount of particles consumed in the flow measurement experiment using the particle image flow meter in the towing tank, and to easily adjust the particle concentration in the measurement area in response to changing experimental conditions.

도 1은 본 발명의 실시 예에 따라 예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 조건과 동일한 조건으로 전산 유체 역학을 이용하여 유동 해석을 수행한 결과.
도 2는 본 발명의 실시 예에 따라 전산 유체 역학을 이용하여 예측된 유체 흐름을 통해서 측정 영역 내로 유입되는 유동의 상류 지점을 파악한 상태.
도 3은 본 발명의 실시 예에 따라 측정 영역 내로 유입되는 유동의 상류 지점에 대응하는 영역을 입자 분사 영역으로 결정한 상태.1 is a flow analysis using computational fluid dynamics under the same conditions as the flow measurement experimental conditions using the particle image flow meter in the towing tank according to an embodiment of the present invention.
FIG. 2 is a view illustrating an upstream point of a flow flowing into a measurement region through a predicted fluid flow using computational fluid dynamics according to an exemplary embodiment of the present invention. FIG.
3 is a state in which a particle injection region is determined as an area corresponding to an upstream point of the flow flowing into the measurement region according to an exemplary embodiment of the present invention.

이하, 첨부된 도면들을 참조하여 본 발명에 대하여 상세히 설명한다. 한편, 본 발명을 설명함에 있어, 관련된 공지 구성 또는 기능에 대한 구체적인 설명이 본 발명의 요지를 흐릴 수 있다고 판단되는 경우에는 그 상세한 설명은 생략한다.
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Meanwhile, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

전산 유체 역학(CFD, Computational Fluid Dynamics)은 유체 유동 현상을 예측하기 위하여 유체 흐름의 지배 방정식인 나비에-스토크스 방정식(Navier-Stokes Equations)을 FDM(Finite Difference Method), FEM(Finite Element Method), FVM(Finite Volume Method) 등과 같은 수치 기법(Numerical method)들을 이용하여 푸는 유체 역학의 한 분야이다.
Computational Fluid Dynamics (CFD) uses the Navier-Stokes Equations (FDM), Finite Difference Method (FDM), and Finite Element Method (FEM) to predict fluid flow phenomena. It is a field of fluid mechanics that solves using numerical methods such as finite volume method (FVM).

본 발명은 예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 시 상술한 전산 유체 역학 해석을 통하여 측정 영역 내에 효과적으로 입자를 분사하는 방법을 제공하고자 하는바,
The present invention is to provide a method for effectively injecting particles in the measurement area through the above-described computational fluid dynamics analysis in the flow measurement experiment using the particle image flow meter in the towing tank,

이러한 목적을 달성하기 위한 본 발명은, 예인수조(6)에서의 입자영상유속계를 이용한 유동 측정 실험 조건과 동일한 조건으로 전산 유체 역학을 이용하여 유동 해석을 수행하는 단계 및; 예측된 유체 흐름을 통해서 측정 영역(2) 내로 유입되는 유동의 상류 지점(3)을 파악하고 이 지점을 입자 분사 영역(4)으로 결정하는 단계;를 포함하여 이루어진다. 이하 도 1 내지 도 3을 참조하여 본 발명에 대하여 단계적으로 상세히 설명한다.
The present invention for achieving this object, the step of performing flow analysis using computational fluid dynamics under the same conditions as the flow measurement experimental conditions using the particle image flow meter in the towing tank (6); Identifying an upstream point 3 of the flow entering the measurement zone 2 through the predicted fluid flow and determining this point as the particle injection zone 4. Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 3.

먼저, 예인수조(6)에서의 입자영상유속계를 이용한 유동 측정 실험 조건과 동일한 조건으로 전산 유체 역학을 이용하여 유동 해석을 수행한다. 도 1은 본 발명의 실시 예에 따라 전산 유체 역학을 이용하여 유동 해석을 수행한 결과를 보여준다. 도 1에는 평균유동장의 유선(Streamline)이 나타나 있는바, 평균유동장의 유선은 시간에 따른 유동 특성의 변화가 크지 않을 때 유체 입자의 이동 경로를 근사적으로 나타낼 수 있다.
First, flow analysis is performed using computational fluid dynamics under the same conditions as the flow measurement experiment conditions using the particle image flow meter in the towing tank 6. 1 shows the results of performing a flow analysis using computational fluid dynamics according to an embodiment of the present invention. 1 shows a streamline of an average flow field, and the streamline of the average flow field may roughly represent a movement path of fluid particles when the change in flow characteristics with time is not large.

다음으로, 도 1에서 예측된 유체 흐름을 통해서 측정 영역(2) 내로 유입되는 유동의 상류 지점(3)을 파악해 낸다. 도 2는 본 발명의 실시 예에 따라 측정 영역(2) 내로 유입되는 유동의 상류 지점(3)을 파악한 상태를 보여준다.
Next, the upstream point 3 of the flow flowing into the measurement region 2 through the fluid flow predicted in FIG. 1 is identified. 2 shows a state of grasping the upstream point 3 of the flow flowing into the measurement zone 2 according to an embodiment of the invention.

이때 유동의 상류 지점(3)은 도 1 및 도 2에서 측정 영역(2)을 지나는 유선을 상류 방향으로 따라 움직인 영역을 의미한다. 이 경우 이러한 유동의 상류 지점(3)에 존재하는 입자는 대부분 다른 영역으로 분산되지 않고 모두 측정 영역(2) 내로 유입된다. 물론 유동의 상류 지점(3) 이외의 다른 영역에 존재하는 입자는 거의 측정 영역(2) 내로 유입되지 않는다.
In this case, the upstream point 3 of the flow means a region in which the streamline passing through the measurement region 2 is moved in the upstream direction in FIGS. 1 and 2. In this case, the particles present at the upstream point 3 of this flow are mostly introduced into the measurement region 2 without being dispersed into other regions. Of course, particles present in regions other than the upstream point 3 of the flow are rarely introduced into the measurement region 2.

따라서 실험자는 관심의 대상인 측정 영역(2) 내로 대부분의 입자가 유입될 수 있도록 유동의 상류 지점(3)을 입자 분사 영역(4)으로 결정한다. 이때 입자 분사 영역(4)은 도 3에 도시된 바와 같이 예인전차(5)가 이동하는 방향 쪽에 정지해 있는 유체의 영역(4)에 대응하므로, 이 영역(4)에 대해서만 입자를 분사하면 하류의 측정 영역(2) 내 유동을 효과적으로 관측할 수 있다.
The experimenter thus determines the upstream point 3 of the flow as the particle injection zone 4 so that most of the particles can flow into the measurement zone 2 of interest. At this time, since the particle spraying region 4 corresponds to the region 4 of the fluid which is stationary on the side of the towing vehicle 5 as shown in FIG. 3, when the particles are injected only to the region 4, the particles are downstream. It is possible to effectively observe the flow in the measurement region 2 of.

따라서 본 발명에 따르면 실험 시 입자를 유동의 상류 지점(3)에만 분사하고 다른 지점에는 분사하지 않아도 되므로 입자의 소비량을 줄일 수 있다. 그리고 변화하는 실험 조건에 대응하여 측정 영역(2) 내의 입자 농도를 용이하게 조절할 수 있다.
Therefore, according to the present invention, it is possible to reduce the consumption of particles because the particles need to be sprayed only at the upstream point 3 of the flow and do not need to be sprayed at other points. The particle concentration in the measurement region 2 can be easily adjusted in response to changing experimental conditions.

이상의 설명은 본 발명의 기술 사상을 예시적으로 설명한 것에 불과한 것으로서, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자라면 본 발명의 본질적인 특성에서 벗어나지 않는 범위 내에서 다양한 수정, 변경 및 치환이 가능할 것이다. 한편, 본 발명의 보호 범위는 아래의 청구범위에 의하여 해석되어야 하며, 그와 동등한 범위 내에 있는 모든 기술 사상은 본 발명의 권리범위에 포함되는 것으로 해석되어야 할 것이다.It will be apparent to those skilled in the art that various modifications, substitutions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. will be. On the other hand, the protection scope of the present invention should be interpreted by the claims below, and all technical ideas within the equivalent scope will be construed as being included in the scope of the present invention.

1 : 물체
2 : 측정 영역
3 : 측정 영역 내로 유입되는 유동의 상류 지점
4 : 입자 분사 영역
5 : 예인전차
6 : 예인수조1: object
2: measurement area
3: upstream point of the flow into the measuring zone
4: particle spraying area
5: Towing Tank
6: towing tank

Claims (1)

예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 조건과 동일한 조건으로 전산 유체 역학을 이용하여 유동 해석을 수행하는 단계 및;
예측된 유체 흐름을 통해서 측정 영역 내로 유입되는 유동의 상류 지점을 파악하고 이 지점을 입자 분사 영역으로 결정하는 단계;
를 포함하는, 예인수조에서의 입자영상유속계를 이용한 유동 측정 실험 시 전산 유체 역학 해석을 통하여 측정 영역 내에 효과적으로 입자를 분사하는 방법.Performing flow analysis using computational fluid dynamics under the same conditions as the flow measurement experiment conditions using the particle image flow meter in the towing tank;
Identifying an upstream point of the flow entering the measurement zone through the predicted fluid flow and determining this point as the particle injection zone;
In the flow measurement experiment using a particle image flow meter in a towing tank comprising a method for effectively injecting particles in the measurement area through computational fluid dynamics analysis.
KR1020110039941A 2011-04-28 2011-04-28 method of seeding particle into towing tank effectively using CFD in application of particle image velocimetry KR20120121999A (en)

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