JPH0820392A - Wing of hydrofoil craft, aircraft, etc. and method of determining optimum shape thereof - Google Patents

Abstract

PURPOSE: To make a design correction in quick response to a given situation by applying the optimum shape to a wing body by experiment, and forming the wing body into a wing cross sectional shape expressed by specific equations capable of strictly indicating the wing body shape. CONSTITUTION: The tip of a wing body 1 is set as an origin O, a coordinate axis toward the rear end of the wing body 1 is set as the x-axis, a coordinate axis perpendicular to the x-axis through the origin O is set as the y-axis, the x-coordinate and y-coordinate of the position where the thickness of the wing body 1 becomes the maximum are set as (a) and (b) respectively, and the x- coordinate and y-coordinate of the end face rear end of the wing body 1 are set as (c) and (yt ) respectively. Two front section shape factors satisfying the relation (m)×(n)=1 are set as (m) and (n), and the rear section shape factor is set as (p). The wing cross sectional shape is expressed by equations y=(b/ a) a<m> -(a-x)<m> }, where 0<=x<=a and y= (yt -a)/(c-a)}<p> +b, where a<x<=c. A wing with a large lift/drag ratio can be easily obtained by above equations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lift generating blade for generating a lift on a hydrofoil ship, an aircraft or the like moving in a fluid. More specifically, in order to increase the ratio defined by lift / drag, an optimum shape is given to the wing body through experiments to form a wing cross-sectional shape represented by a mathematical expression so that the wing body shape can be strictly expressed. Wings of hydrofoil ships, aircraft, etc.

[0002]

2. Description of the Related Art Propeller blades such as aircraft blades, underwater boat blades, and propeller-constituting blades that constitute propellers have a thickness shape and a camber, whether they are rotor blades or lift-generating blades. For example, when the propeller rotates in an imperfect fluid such as water or air, the fluid velocities with respect to the front surface (suction surface) and the rear surface (pressure surface) of the rotor blade are different from each other. When the fluid velocities are different, a pressure difference occurs between the front surface and the rear surface according to Bernui's theorem.

In order for propellers and blades to generate thrust, the pressure on the rear surface must be greater than the pressure on the upper surface or front surface. That is, the fluid velocity for the top or front surface must be faster than the fluid velocity for the bottom or back surface.

In order for the horizontal blades and rotary blades to generate large lift and thrust, the pressure around the blades is lower than the upper surface, rather than the rear surface.
Must be as low as possible at the front. In the case of a hydrofoil, such low pressure vaporizes water and creates cavities. If the cavity thus generated collapses and ruptures after flowing completely over the entire surface of the hydrofoil, it will only generate noise and will not cause corrosion damage to the wing,
If the cavity collapses and bursts before it completely flows over the entire surface of the hydrofoil, the impact of the burst during the collapse causes corrosion damage to the blade.

[0005] Cavitation not only causes corrosion damage, but also reduces propulsion efficiency. End face shapes for reducing such adverse effects have been developed and known in various countries. NACA-Series end face developed in the United States,
B-Series end faces developed in the Netherlands and MAU-Series end faces developed in Japan are known.

[0006]

The known end face shape is completely fixed. When the size is changed, the function that determines the shape changes. Therefore, the pressure distribution around the blade cannot be adjusted by quickly adjusting the shape of the blade tip surface. According to the known fixed shape of the blade, if the blade is designed and manufactured to cause excessive peeling phenomenon and cavity phenomenon, the design must be modified and remanufactured, but it is possible to immediately respond to a given situation. I can't redo the design, so
There was a problem in that time and economic burdens were great for re-production.

The present invention has been made based on such a technical background, and achieves the following objects.

An object of the present invention is to provide a wing of a hydrofoil ship, an aircraft, or the like having a shape that can be represented by a variable mathematical expression that can be designed and modified in response to a given situation quickly.

It is an object of the present invention to provide a wing of a hydrofoil ship, an aircraft or the like having a shape represented by a variable mathematical expression capable of rigorously expressing an optimum shape recognized in an experiment.

Still another object of the present invention is to provide a wing of a hydrofoil ship, an aircraft, or the like having a shape represented by a mathematical expression specifying an optimum shape parameter in comparison with a conventional shape. .

Still another object of the present invention is to provide a method for determining an optimal shape of a wing of a hydrofoil ship, an aircraft, etc., for determining an optimal shape represented by a variable mathematical expression for a given situation. Is to do.

This optimum shape determination method is performed by using a mathematical formula that can change the blade shape without changing the maximum thickness b, the blade width c, and the position a where the maximum thickness is obtained.

[0013]

[Means for Solving the Problems] To solve the above problems, the following means are adopted.

The wing of the hydrofoil ship, aircraft, etc. of the first invention is
The coordinate axis extending from the tip of the wing body to the rear end of the wing body is the x-axis, and the coordinate axis passing through the origin and orthogonal to the x-axis is y.
X-coordinate and y at the position where the thickness of the wing body is the maximum
The coordinates are a and b, respectively, and x at the rear end of the wing body
The coordinates and y coordinates are respectively c and yt, and m * n =
Assuming that the two front part shape indices satisfying 1 are m and n and the rear part shape index is p,

[0015]

[Equation 1]

[0016]

It is formed in a blade cross-sectional shape represented by the following equation.

The method for determining the optimum shape of a wing of a hydrofoil ship, an aircraft, etc. of the invention 2 is the method of determining the optimum shape of a wing of a hydrofoil ship, an aircraft, etc. of the invention 1, wherein the constant a , B, and c are fixed, and at least one of the shape indices p and n is changed to determine the shape indices p and n that give the optimum shape.

The method for determining the optimum shape of a wing of a hydrofoil or an aircraft according to a third aspect of the present invention is the method for determining the optimum shape of a wing of a hydrofoil ship or an aircraft according to the first aspect of the present invention. , The first to produce the wing body by reproducing the above equation
A manufacturing step, a test step of performing a performance test of the wing body in a fluid with the wing body manufactured in the first manufacturing step, and newly defining the shape indices n and p based on the test. And a second test step of performing a performance test of the wing body in a fluid using the wing body manufactured in the second manufacturing step.

The method for determining the optimum shape of a wing of a hydrofoil or an aircraft according to the fourth aspect of the present invention is the method according to the third aspect, wherein the constant a,
At least one of the shape indices n and p is changed without changing b and c.

[0020]

The wings of hydrofoils, aircraft, etc. and the method for determining the optimum shape thereof according to the present invention exactly reproduce the shape that can be confirmed by experiments. Determine the optimal wing tip shape without changing the size and dimensions. The end face shape determined in this way is strictly reproduced.

[0021]

【Example】

(Embodiment 1) Next, an embodiment of the present invention will be described.
FIG. 1 is a sectional view showing a section of a wing of an aircraft or a hydrofoil according to the first embodiment of the present invention. In order to strictly formulate this cross-sectional shape, a coordinate system is set in FIG.

The origin of the Cartesian coordinates xy is represented by O. The origin O is set as the tip point of the wing body 1. The positive direction in the x-axis direction coincides with the tail end direction of the wing body 1. Let the y-axis direction be the thickness direction of the wing body 1. The coordinates (x, y) at which the thickness becomes maximum are defined as (a, b). Both constants a and b are positive. The coordinates of the tail end on the upper surface of the wing body are represented by (c, yt). The blade shape line 2 obtained by cutting the upper end surface of the blade body 1 in the xy plane is generally represented by y = f (x). The wing body 1 is divided into a wing front part 3 and a wing rear part 4, and the wing shape is considered. First, the wing front portion 3 will be considered. At x = 0, the derivative of the wing shape line 2 diverges,
A condition is set in which the shape is smooth as a whole and the derivative becomes zero at the coordinates (a, b) at which the thickness becomes maximum. The above-mentioned condition is satisfied by using an index n smaller than 1 and a shape index m such that m * n = 1 as a shape index, which is a parameter of the shape of the wing front portion 3 in front of the position where the thickness is maximum. the function is,

[0023]

It can be expressed by: Differentiating this equation gives

[0024]

[Equation 2] Here, k is a constant. In equation (1), when a is substituted for x, y is indeed b, and when zero is substituted for x in equation (2), the differential coefficient dy / dx does diverge. When a is substituted for x in equation (2), the differential coefficient is certainly zero.

Next, the wing rear portion 4 will be considered. At the coordinates (a, b) where the thickness becomes maximum, the derivative becomes zero, the shape is continuous with the shape of the wing front part 3, and the coordinates of the tail end point are (c,
yt) is given to the shape of the wing rear part 4. A function that satisfies this condition is to use a shape index p of the wing rear portion 4 that is greater than 1 to

[0026]

It is expressed by Differentiating this equation gives

[0027]

[Equation 4] Here, j is a constant. Substituting c for x in equation (3), y is certainly b, and substituting a for x in equation (4),
The derivative is certainly zero. The upper end surface and the lower end surface of the blade body 1 may be symmetrical with respect to the x axis.

FIG. 2A shows that n = 0.2, 0.4, 0.
For 6 and 0.8, the shape of the wing front part 3 is shown.
In the graph of FIG. 2, the horizontal axis is x / c, and the vertical axis is y / 2b.
Is. FIG. 2B shows that p = 1.25, 1.50, 1..
The shape of the wing rear part 4 is shown for 75 and 2.00. The horizontal axis is x / c and the vertical axis is y / 2b.

FIG. 3 shows a comparison between the conventional wing and the wing of the present invention. The vertical axis is y / c unlike FIG. The horizontal axis is x / c as in FIG. The conventional end face shapes that are currently most frequently used worldwide are the end face shape of the NACA00 series of the NACA00 series shown by the dotted line of the long line segment and the NACA66 series of the NACA66 series shown by the dotted line of the short line segment.
Two of the end face shapes 66-009 are shown. The solid line indicates the end face shape of the present invention. This end face shape is
n = 0.6 and p = 1.25.

FIG. 4 shows the comparison between the end face shape of NACA 66-009 (shown by a dotted line) and the end face shape of HMR1NP-009 of the present invention (shown by a solid line). This comparative test is based on the HSVA (Hamburug S
This is a test using a model in the hip model basin.
In FIG. 4, the left vertical axis shows the lift coefficient (CL) and the drag coefficient (10 * CD), and the right vertical axis is the ratio LIFT /
DRAG, that is, CL / CD. This ratio is denoted as L / D. The horizontal axis indicates the angle of attack.

As can be seen from FIG. 4, the L / D ratio of the present invention, that is, the lift / drag, shows a large value at all angles of attack as compared with the conventional one. As described above, the superiority of the present invention can be understood from the test results by the laboratory.

The sizes and dimensions of the aircraft wings and hydrofoil wings are almost automatically determined according to user requests. For example, engine horsepower, hull weight,
The length, width, etc. of the hydrofoil are almost automatically determined from the user's request. Therefore, the width c, the maximum thickness b, and the coordinates a of the end face shape position at which the thickness is the maximum are defined as constants of the design specification. Once the appropriate shape indices n and p are determined, the blade main body (including the model blade) having the end face shape defined by the equations (1, 3) is manufactured by the NC multi-axis machine tool.

The wing body manufactured in this manner is placed in a fluid, and the performance such as the pressure distribution on the end face and the performance test shown in FIG. 4 are performed. The shape indices n and p are changed according to the pressure distribution abnormality and the performance test result. The wing body is manufactured again with the new shape index after the correction. A performance test is performed again using the wing body that was manufactured again. Such retesting is performed at least once to determine the shape indices n and p of the optimum end surface shape.

After changing the constants a, b, and c of the design specification, the optimum shape is determined by the above-mentioned steps, that is, the steps of the first manufacturing step, the first test step, the second manufacturing step, and the second test step. This is also included in the step of determining the shape indexes n and p of the optimum end face shape.

[0035]

Other Embodiments The end face shape according to the present invention is not limited to hydrofoil ships and aircraft wings, but also gliders, model airplanes,
It can be applied to moving bodies that require lift such as model ships. Moreover, it is applied to a moving body relative to a fluid, and is also applied to a current plate. Without fixing the position of the maximum thickness, that is,
It is also possible to determine the shape indices n and p by changing one, two, or three of the values of a, b, and c in the formula, and obtain the optimum shape.

[0036]

According to the method for determining the wing of a hydrofoil ship, an aircraft or the like and the optimum shape thereof according to the present invention, it is possible to determine the optimum shape of the wing which obtains the largest lift or the highest lift / drag under the same conditions. . The present invention is the world's first variable-wing wing under the same conditions after several years of strenuous efforts, and it is very effective for the design of aircraft wings for hydrofoil. The pressure distribution can be adjusted economically and appropriately, the separation and cavitation phenomena can be controlled economically, and at the same time, a highly efficient wing can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating setting of coordinate axes for expressing a wing tip surface shape of a wing of a hydrofoil ship, an aircraft, or the like according to the present invention.

FIG. 2 is a cross-sectional view showing a front part (leading part) of a wing body when a shape index is changed; FIG. It is sectional drawing which shows the back part (tail part) of a wing main body.

FIG. 3 is a cross-sectional view for comparing an end face shape of the present invention with an existing end face shape.

FIG. 4 is a graph showing a characteristic comparison between an end face shape of the present invention and an existing end face shape.

[Explanation of symbols]

 1 wing body 2 wing shape line 3 wing front part 4 wing rear part

Claims (4)

[Claims] A position at which the thickness of the wing body is maximized, wherein a coordinate axis extending from the leading end of the wing body to the rear end of the wing body is defined as an x-axis and a coordinate axis passing through the origin and orthogonal to the x-axis is defined as a y-axis. X and y coordinates of the wing body are a and b, respectively, and the x and y coordinates of the rear end of the end surface of the wing body are c and y, respectively.
Assuming that t is t, two front shape indices satisfying m * n = 1 are m, and n and rear shape index are p, (Equation 3) A wing of a hydrofoil ship, aircraft, etc., having a wing cross-sectional shape represented by. 2. The method according to claim 1, wherein the constants a, b, and c are fixed and at least one of the shape indices p, n is determined. Shape indices p, n to be changed to give optimal shape
A method for determining the optimal shape of a wing of a hydrofoil ship, aircraft, etc. 3. A method for determining an optimum shape of a wing of a hydrofoil ship, an aircraft or the like according to claim 1, further comprising the step of providing said shape indices n and p and reproducing said formula to produce a wing body. 1 manufacturing step; a test step of performing a performance test of the wing body in the fluid with the wing body manufactured in the first manufacturing step; and newly determining the shape indices n and p based on the test. Determination of the optimal shape of a wing of a hydrofoil ship, aircraft, etc., comprising a second manufacturing step of manufacturing a main body and a second test step of performing a performance test of the wing main body in a fluid with the wing main body manufactured in the second manufacturing step. Method. 4. The method according to claim 3, wherein at least one of the shape indices n and p is changed without changing the constants a, b and c.