JP2015147476A - Craft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a craft that has a ship shape capable of reducing pressure resistance and friction resistance, acting on a hull, without decreasing wake gain (propeller efficiency).SOLUTION: A craft 100 has a ship shape in which a beam is maximized in a maximum beam position C at a distance equivalent to 55-85% of a between-perpendiculars length Lpp being a distance between a stern perpendicular AP and a bow perpendicular FP, from a stern 15, and in which the beam is linearly decreased toward the stern 15, between the maximum beam position C and an inclination end position D at a distance equivalent to 25-42% of the between-perpendiculars length Lpp from the stern 15.

Description

  The present invention relates to a ship, and more particularly, to a ship having a hull form with reduced resistance during operation.

  Conventionally, in order to improve propulsion efficiency during operation, L. When floating in a stationary state, at least 5% of the length between the vertical lines of the hull is provided below the first horizontal plane before the center of the hull with respect to the first horizontal plane at the draft depth in the middle of the hull. A ship-shaped ship is disclosed (for example, see Patent Document 1).

Japanese Patent Laying-Open No. 2012-180021 (page 8-9, FIG. 1)

  The ship disclosed in Patent Literature 1 is a navigation of a displacement-type ship that transports at least one of cargo and passengers in a range where the length between perpendiculars is in the range of 100 m to 400 m and the planned navigation speed is in the range of 10 knots to 40 knots. In the method, before the center of the hull, it is a method of navigating in a state in which at least 5% or more of the length between perpendiculars of the hull is below the first horizontal plane with respect to the first horizontal plane at the draft depth at the center of the hull. Therefore, it is possible to navigate in full load draft and light draft draft in the same state as the bow trim state with good propulsion efficiency. Therefore, the propulsion efficiency at the time of operation can be improved, the fuel consumption can be reduced, the carbon dioxide emission can be reduced, and the depth of the hull becomes deeper. It is said that there will be less restrictions on the shape.

However, the ship disclosed in Patent Document 1 has the following problems because the ship bottom is inclined so that the ship bottom on the stern side becomes shallow.
That is, by inclining the ship bottom, the flow velocity on the propeller surface is increased, and the wake gain (propeller efficiency) is deteriorated as compared with a ship having a horizontal ship bottom.

  The present invention solves such a problem, and an object of the present invention is to provide a ship having a hull form that can reduce pressure resistance and friction resistance acting on the hull without deteriorating wake gain (propeller efficiency). And

(1) The ship according to the present invention has the largest ship width at the maximum ship width position at a distance of 55 to 85% of the length between the perpendicular lines, which is the distance between the stern perpendicular line and the bow perpendicular line. Between the slope end position and the maximum ship width position at a distance of 25 to 42% of the length between the vertical lines to the stern.
(2) Also, in (1) above, Cb when the length between the perpendiculars is Lpp, and there is a completely parallel part that is more than half of Lpp, the ship width is B, the full draft is d, and the drainage volume is ▽ (= For comparison vessels with a value of ▽ / (Lpp · B · d)) of 0.8 or more,
The same vertical length as above, the same full draft as above, the same drainage volume as above, and when the ship width at the maximum ship width position is Bc, the inclination end position and the maximum ship width position The angle (θc) between the ship side in the full draft during the period and the hull centerline at the midpoint of the inclined part is
θ = a · x ² + b · x + c
a = 0.1024 + 0.0011 · (Lpp / (2 · B) −2)
b = −2.0889−0.0922 · (Lpp / (2 · B) −2)
c = 97.344 + 3.2111 · (Lpp / (2 · B) −2)
x = Lpp · α
Bc ≦ (Lpp · 0.315)
0.55 ≦ α ≦ 0.85
4 ≦ (Lpp / B) ≦ 8
(0 <θc <θ) smaller than the effective inclination angle (θ) determined by
(3) In (1) or (2), the angle between the ship side in the full draft and the hull center line between the end position of inclination and the maximum position of the ship width is 10 ° or less. Features.
(4) Further, in (1) to (3), the length between the perpendiculars is 200 m or more, and the Cb value is 0.8 or more.

  The ship of the present invention works on the hull without deteriorating the wake gain (propeller efficiency) because the ship width decreases linearly as it approaches the stern between the maximum ship width position and the end position of inclination. Pressure resistance and frictional resistance can be reduced. The “straight line” is not limited to a strict straight line, but also means a substantially straight line including a smooth curve.

BRIEF DESCRIPTION OF THE DRAWINGS The top view which shows the hull form of the ship which concerns on embodiment of this invention, Comprising: The waterline surface shape (only the left ship side) in a full load draft. FIG. 2A is a characteristic diagram showing a distribution of pressure resistance coefficients, and FIG. 2B is a bar graph for comparing pressure resistances. FIG. 3A is a characteristic diagram illustrating a distribution of a non-dimensional coefficient of frictional resistance, and FIG. 3B is a bar graph for comparing frictional resistances. FIG. 2 is a characteristic diagram for explaining the effect of the maximum ship width position in the ship shown in FIG. 1 on resistance reduction, in which the horizontal axis is the maximum ship width position C, and the vertical axis is the resistance reduction rate ((Rt−Rt0) / Rt0). value. The characteristic view explaining the effect which the inclination angle in the ship shown in FIG. 1 has on the resistance reduction (when the maximum ship width distance Lc is 85% of the length Lpp between the stern and the perpendicular). The characteristic view explaining the effect which the inclination angle in the ship shown in FIG. 1 has on the resistance reduction (when the maximum ship width distance Lc is 70% of the length Lpp between the stern and the perpendicular). The characteristic view explaining the effect which the inclination angle in the ship shown in FIG. 1 has on the resistance reduction (when the maximum ship width distance Lc is 55% of the length Lpp between the stern and the perpendicular). The effect of the maximum ship width distance and the tilt angle on the resistance reduction in the ship shown in FIG. 1 will be described.

[Embodiment]
FIG. 1 is a plan view illustrating a hull form of a ship according to an embodiment of the present invention and showing a waterline shape (only on the left ship side) in a full draft.
In FIG. 1, the X-axis indicates the hull center line (CL) 10 and the Y-axis indicates the ship width direction. The distance between the bow perpendicular FP and the stern perpendicular AP (the rudder axis position) is “inter-perpendicular length (Lpp)”, and the position at the same distance from the bow perpendicular FP and the stern perpendicular AP is the hull center position (M.S. ).
The hull form in the full draft of the ship 100 has the largest ship width at a position close to the bow 11 (hereinafter referred to as “maximum ship width position”), the maximum ship width position C, and the stern vertical line position (hereinafter referred to as “stern”). Between the position 15 (referred to below as “tilt end position”) D and the position (hereinafter referred to as “tilt end position”) that is approximately 1/3 of the length between the vertical lines (Lpp) from 15 The width of the stern decreases as the stern 15 is reached. It should be noted that the space between the bow normal position (hereinafter referred to as “the bow”) 11 and the maximum ship width position C is referred to as “the bow range 12” and the space between the tilt end position D and the stern 15 is referred to as “stern range 14” for convenience. .

The value of the ship width at the maximum ship width position C (hereinafter referred to as “maximum ship width Bc”), the value of the distance between the stern 15 and the maximum ship width position C (hereinafter referred to as “maximum ship width distance Lc”), The value of the angle formed by the inclined portion 13 with the hull center line (hereinafter referred to as “inclination angle θc”) will be described in detail separately.
The ship 100 basically defines the hull form below the full load water line (main part on the ship side) and does not limit the hull form above the full water line. For each draft, the value of the inclination angle θc may be different from the value below the full draft line.
That is, the ship side above the full load water line needs to consider the continuity with the shape below the surface of the water, but may not have the inclined portion 13 or may be the inclined portion 13 (water surface as well as below the water surface). It may be different from the lower inclination angle θc).

On the other hand, the broken line in FIG. 1 shows the hull form of the conventional ship 90. That is, a bow range 92 is formed between the bow 11 and the position Af, a parallel portion 93 is formed between the position Af and the position Aa, and a stern range 94 is formed between the position Aa and the stern 15. The parallel portion 93 is parallel to the hull center line 10 and the distance between the right ship side and the left ship side in the parallel portion 93 is “ship width B”.
At this time, the maximum ship width Bc of the ship 100 is larger than the ship width B of the ship 90. That is, in order to compensate for the decrease in the amount of drainage due to the inclined portion 13, both drainage amounts are made the same as “Bc> B”. Therefore, as the inclination angle θc is larger, the bow range 12 becomes wider to the vicinity of the bow 11 and the amount of drainage increases. On the contrary, the stern range 14 extends from the inclined portion 13 to the stern 15 and becomes narrower. The amount of drainage will be reduced. The ratio of the maximum ship width Bc to the ship width B (Bc / B) is referred to as “ship width increase rate”.

(Pressure resistance)
2 explains the characteristics of the ship shown in FIG. 1. FIG. 2 (a) is a characteristic diagram showing the distribution of the pressure resistance coefficient (Cp), and FIG. 2 (b) is the pressure resistance (Rp). ). The pressure resistance coefficient is a dimensionless coefficient of pressure resistance,
“Cp = Rp / (0.5 · ρ · u ² · S)”
It can be expressed as Where ρ is the fluid density, u is the hull speed, and S is the flooded area.
In FIG. 2A, the horizontal axis is the distance in the direction of the bow 11 from the stern 15, where “0.0” corresponds to the stern 15 and “1.0” corresponds to the bow 11. The left vertical axis indicates the position on the ship side, and corresponds to a “curve that protrudes upward” in which both ends in the figure are “0.0”. Further, the vertical axis on the right side shows the pressure resistance coefficient (Cp), and both ends in the figure increase upward and correspond to a “curved curve” in the central range. In addition, the broken line indicates the ship 100 and the solid line indicates the ship 90, respectively.

This characteristic diagram is a calculation result using a theoretical calculation tool (CFD: Computational Fluid Dynamics), in which the ship width increase rate (Bc / B) is 7.5% and the inclination angle (θc) is 1.2 °. This is a case, which is at a draft position (10.0 m) which is about half of the full draft (19.2 m).
In both the ship 100 and the ship 90, the pressure resistance coefficient increases as it approaches the stern 15, and similarly, the pressure resistance coefficient increases as it approaches the bow 11, and in a range including the hull center position (MS). Although it has a slightly convex curve, the pressure resistance coefficient decreases rapidly as it approaches the bow 11. That is, the value of the horizontal axis is in the vicinity of 0.8, and a valley shape is exhibited.

  In FIG. 2B, bar graphs are obtained by integrating the pressure resistance coefficient (Cp) shown in FIG. 2A over the entire length. That is, when the integrated value of the ship 90 having the parallel part 93 is 100%, the integrated value of the ship 100 having the inclined part 13 is about 92%, which is reduced by about 8%.

(Frictional resistance)
FIG. 3 explains the characteristics of the ship shown in FIG. 1. FIG. 3 (a) is a characteristic diagram showing the distribution of the dimensionless coefficient (Cf) of the frictional resistance, and FIG. It is a bar graph which compares friction resistance (Rf). The frictional resistance coefficient is a dimensionless coefficient of frictional resistance,
“Cf = Rf / (0.5 · ρ · u ² · S)”
It can be expressed as
In FIG. 3A, the vertical axis on the right side shows the dimensionless coefficient (Cf) of the frictional resistance, and both ends in the figure decrease downward, and are mountain-shaped convex upward in the range close to the bow 11. It is a curve. The broken line indicates the ship 100 and the solid line indicates the ship 90, and the horizontal axis and the right vertical axis are the same as those in FIG.
That is, the dimensionless coefficient (Cf) of the frictional resistance is slightly larger for the ship 100 (broken line) than the ship 90 (solid line) when the value on the horizontal axis is around 0.85, but at other positions, The ship 100 is slightly smaller than the ship 90.

  In FIG. 3B, a bar graph is obtained by integrating the dimensionless coefficient (Cf) of the frictional resistance shown in FIG. 3A over the entire length. That is, when the integrated value of the ship 90 having the parallel part 93 is 100%, the integrated value of the ship 100 having the inclined part 13 is about 99%, which is reduced by about 1%.

(Required horsepower)
From the above, when the required horsepower is calculated based on the hull resistance values of the ship 100 and the ship 90, the ship 100 having the inclined portion 13 requires approximately 2% less horsepower than the ship 90 having the parallel portion 93. The result is obtained.

(Effect of maximum ship width position)
FIG. 4 is a characteristic diagram for explaining the effect of the maximum ship width position in the ship shown in FIG. 1 on the resistance reduction. The horizontal axis represents the maximum ship width position C (same as the maximum ship width distance Lc), and the vertical axis Indicates the value of the resistance reduction rate ((Rt−Rt0) / Rt0). The resistance reduction rate ((Rt−Rt0) / Rt0) is a reduction rate of the resistance (Rt) of the ship 100 with respect to the resistance (Rt0) of the ship 90, and “0.0%” when both are the same. The case where the resistance (Rt) of the ship 90 is 90% of the resistance (Rt0) of the ship 100 is defined as “−10%”.
In FIG. 4, when the maximum ship width distance Lc is in the range of 55 to 85% of the length Lpp between the stern 15 (Lc = Lpp · α, 0.55 ≦ α ≦ 0.85), the resistance decreasing rate ((Rt The value of −Rt0) / Rt0) is lower than “−10%”.
That is, by arranging the maximum ship width position C in the range of 55 to 85%, the resistance can be made 10% or more smaller than that of the ship 90 not having the inclined portion 13 (having the parallel portion 93). I understand.

(Effect of tilt angle)
5 to 7 are characteristic diagrams for explaining the effect of the inclination angle in the ship shown in FIG. 1 on the resistance reduction, and the maximum ship width distance Lc is 85% and 70% of the length Lpp between the stern and the vertical line, respectively. , 55% resistance reduction rate ((Rt−Rt0) / Rt0). The horizontal axis is the inclination angle (θc [deg]), and the vertical axis is the same as in FIG. 4. As a parameter, the ratio of the length Lpp between perpendiculars to the ship width B (hereinafter referred to as “ship width ship length ratio Lpp / B”). ) Shows the cases of 4, 6 and 8. These are obtained using a theoretical calculation tool (CFD: Computational Fluid Dynamics).

In FIG. 5, when the maximum ship width distance Lc is 85% of the stern-to-perpendicular length Lpp and the ship width ratio L / B is 8, the effect of reducing the resistance is obtained when the inclination angle θ is 10 ° or less. The absolute value of the resistance decrease rate ((Rt−Rt0) / Rt0) increases as the angle decreases from 0 ° to approximately 5 °, and the resistance decrease rate ((Rt−Rt0) increases from approximately 5 ° to 10 °. ) / Rt0) is smaller in absolute value. Then, the maximum (about 6.5%) resistance reduction effect is obtained in the vicinity of about 5 °.
Further, when the ship width ratio L / B is 6, an effect of decreasing the resistance is obtained when the inclination angle θ is 13 ° or less, and the resistance decreasing ratio ((Rt−Rt0) increases from 0 ° to about 5 °. ) / Rt0) increases, and the absolute value of the resistance reduction rate ((Rt−Rt0) / Rt0) decreases as it approaches 10 ° from about 5 °. The maximum (about 10.5%) resistance reduction effect is obtained in the vicinity of about 5 °.
Further, when the ship length ratio L / B is 4, an effect of reducing the resistance is obtained when the inclination angle θ is 16 ° or less, and the resistance decreasing rate ((Rt−Rt0) increases from 0 ° to about 10 °. ) / Rt0) increases, and the absolute value of the resistance reduction rate ((Rt−Rt0) / Rt0) decreases as it approaches 16 ° from approximately 10 °. The maximum (about 15.5%) resistance reduction effect is obtained in the vicinity of approximately 10 °.

In FIG. 6, when the maximum ship width distance Lc is 70% of the stern-to-perpendicular length Lpp and the ship width ratio L / B is 8, the effect of reducing the resistance is obtained when the inclination angle θ is 12 ° or less. The absolute value of the resistance decrease rate ((Rt−Rt0) / Rt0) increases as the angle decreases from 0 ° to approximately 7 °, and the resistance decrease rate ((Rt−Rt0) increases from approximately 7 ° to 12 °. ) / Rt0) is smaller in absolute value. The maximum (about 7.0%) resistance reduction effect is obtained in the vicinity of approximately 7 °.
Further, when the ship length ratio L / B is 6, an effect of reducing the resistance is obtained when the inclination angle θ is 14 ° or less, and the resistance decreasing rate ((Rt−Rt0 ) / Rt0) increases, and the absolute value of the resistance reduction rate ((Rt−Rt0) / Rt0) decreases as it approaches 14 ° from approximately 9 °. The maximum (about 10.0%) resistance reduction effect is obtained in the vicinity of about 9 °.
Further, when the ship length ratio L / B is 4, an effect of reducing the resistance is obtained when the inclination angle θ is 16 ° or less, and the resistance decreasing rate ((Rt−Rt0) increases from 0 ° to about 10 °. ) / Rt0) increases, and the absolute value of the resistance reduction rate ((Rt−Rt0) / Rt0) decreases as it approaches 16 ° from approximately 10 °. The maximum (about 16.0%) resistance reduction effect is obtained in the vicinity of approximately 12 °.

In FIG. 7, when the maximum ship width distance Lc is 55% of the stern-to-perpendicular length Lpp and the ship width ratio L / B is 8, the effect of reducing the resistance is obtained when the inclination angle θ is 20 ° or less. The absolute value of the resistance decrease rate ((Rt−Rt0) / Rt0) increases as the angle decreases from 0 ° to approximately 15 °, and the resistance decrease rate ((Rt−Rt0) increases from approximately 15 ° to 20 °. ) / Rt0) is smaller in absolute value. The maximum (about 7.0%) resistance reduction effect is obtained in the vicinity of about 15 °.
Further, when the ship width ratio L / B is 6, an effect of reducing the resistance is obtained when the inclination angle θ is 21.5 ° or less, and the resistance decreasing rate ((Rt The absolute value of -Rt0) / Rt0) increases, and the absolute value of the resistance reduction rate ((Rt-Rt0) / Rt0) decreases as it approaches 21.5 ° from approximately 17 °. The maximum (about 10.0%) resistance reduction effect is obtained in the vicinity of about 17 °.
Further, when the ship length ratio L / B is 4, an effect of reducing the resistance is obtained when the inclination angle θ is 23 ° or less, and the resistance decreasing rate ((Rt−Rt0 ) / Rt0) increases, and the absolute value of the resistance reduction ratio ((Rt−Rt0) / Rt0) decreases as it approaches 23 ° from approximately 16 °. The maximum (about 14.0%) resistance reduction effect is obtained in the vicinity of approximately 16 °.

(Effects of maximum ship width position and tilt angle)
FIG. 8 explains the effect of the maximum ship width distance Lc and the inclination angle θc on the resistance reduction in the ship shown in FIG. 1, wherein the horizontal axis is the maximum ship width distance Lc, and the vertical axis is the effective inclination angle θ. is there.
5 to 7, the effective inclination angle θ is the maximum inclination angle at which the effect of reducing the resistance is obtained, that is, the curve indicating the resistance reduction ratio ((Rt−Rt0) / Rt0) is the X axis (0. 0%) and the same angle of inclination.
In FIG. 8, the effective inclination angle θ decreases as the ship width ship length ratio L / B increases, and the effective inclination angle θ decreases as the maximum ship width distance Lc increases.
Therefore, if the maximum ship width distance Lc is 55 to 85% of the perpendicular length Lpp and the inclination angle θc is 10 ° or less, if the ship width ship length ratio L / B is in the range of 4 to 8, Even if the ship width ratio is L / B, a resistance reduction effect can be obtained.

Furthermore, when the regression equation is obtained for the three curves shown in FIG.
θ = a · x ² + b · x + c
a = 0.1024 + 0.0011 · (Lpp / (2 · B) −2)
b = −2.0889−0.0922 · (Lpp / (2 · B) −2)
c = 97.344 + 3.2111 · (Lpp / (2 · B) −2)
x = Lpp · α
Bc ≦ (Lpp · 0.315)
0.55 ≦ α ≦ 0.85
4 ≦ (Lpp / B) ≦ 8
At this time, the ship width when the same drainage amount as the ship 100 is satisfied and the ship width at a predetermined distance from the stern perpendicular is constant is B.
Therefore, if the “maximum ship width distance Lc” and the “maximum ship width Bc” are selected so as to satisfy the above equation, and the inclination angle θc is smaller than the effective inclination angle θ determined by the above equation, the resistance A reduction effect is obtained.
In the above description, the tilt end position D is set at a position close to the bow side by about (1/3) of the captain from the stern 15, but the present invention is not limited to this, and between the stern 15 and the perpendicular line If it is located within the range of 25 to 42% of the length Lpp, the above effect can be obtained.
Moreover, it is thought that the tendency of each Water Line section is substantially in agreement with a large-sized enlargement ship. In other words, it is considered that the regression equation obtained can be applied to almost all cross-sectional shapes in large-sized enlargement ships.

  According to the present invention, a resistance reduction effect can be obtained by forming an inclined portion that satisfies the above formula, and therefore, it can be widely used as a general large merchant ship shape for various uses.

10 Hull Center Line 11 Bow 12 Bow Range 13 Slope 14 Stern 15 Stern 90 Ship 92 Ship Span 93 Parallel Part 94 Stern 100 Ship θ Slope (Effective Slope)
θc Inclination angle AP Stern perpendicular FP Bow perpendicular Aa Position Af Position B Ship width Bc Maximum ship width C Maximum ship width position D Inclination end position Lc Maximum ship width distance Lpp / B Ship width length ratio Lpp Length between perpendiculars

Claims (4)

  From the stern perpendicular to the stern perpendicular to the bow perpendicular the distance between the perpendiculars is 55 to 85% of the maximum width of the ship, and the width is the largest. A ship having a hull form in which the width of the ship decreases linearly as it approaches the stern between the end position of inclination at a distance of and the maximum position of the ship width. Cb (= ▽ / (Lpp · B · d)) where the length between the perpendiculars is Lpp, the ship has a completely parallel part that is more than half of Lpp, its ship width is B, its full draft is d, and its drainage volume is ▽ For a comparative vessel with a value of 0.8 or more,
The same vertical length as above, the same full draft as above, the same drainage volume as above, and when the ship width at the maximum ship width position is Bc, the inclination end position and the maximum ship width position The angle (θc) between the ship side in the full draft during the period and the hull centerline at the midpoint of the inclined part is
θ = a · x ² + b · x + c
a = 0.1024 + 0.0011 · (Lpp / (2 · B) −2)
b = −2.0889−0.0922 · (Lpp / (2 · B) −2)
c = 97.344 + 3.2111 · (Lpp / (2 · B) −2)
x = Lpp · α
Bc ≦ (Lpp · 0.315)
0.55 ≦ α ≦ 0.85
4 ≦ (Lpp / B) ≦ 8
The ship according to claim 1, wherein the ship is smaller than an effective inclination angle (θ) determined by the equation (0 <θc <θ).   The ship according to claim 1 or 2, wherein an angle formed by a ship side in a full draft between the end position of inclination and the maximum ship width position with a hull center line is 10 ° or less.   The ship according to any one of claims 1 to 3, wherein the length between the perpendiculars is 200 m or more and the Cb value is 0.8 or more.

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