Low-resistance ship form design method for underwater navigation body

Abstract

The invention discloses a low-resistance ship type design method for an underwater vehicle, which comprises the following steps of: selecting square polynomial linear equations with different parameters to determine basic equations of head and tail line types according to technical requirements; according to the allowable value range of the adjustable parameter and the influence of the change of the adjustable parameter on the linetype characteristic, determining the numerical values of one or more groups of adjustable parameters, and obtaining a preliminary linetype; according to the determined basic geometric parameters of the shape of the navigation body and the obtained line types of the head and the tail, a preliminary and complete shape curve of the navigation body is formed; verifying the preliminarily determined shape of the navigation body, and checking whether the preliminarily determined shape of the navigation body meets design requirements or not; and finally, carrying out multiple times of iterative verification through CFD simulation and related experiments. The low-resistance ship type design provided by the invention can effectively cope with complex flow characteristics such as multi-phase, turbulent flow, phase change and unsteady flow characteristics specific to cavitation and turbulent flow, and further meets the design requirements of stability, maneuverability and the like of the underwater navigation body.

Description

Technical Field

[0001] The invention relates to the technical field of ship type design, in particular to a low-resistance ship type design method for an underwater navigation body. Background Art

[0002] The traditional fully submerged underwater vehicle has a maximum speed of about 40m / s (80kn) due to the friction resistance of the wall. If the physical properties of the medium in contact with the wall of the vehicle can be changed globally or locally, especially the viscosity that measures the friction of the fluid, a great breakthrough in speed can be achieved. This design concept has given rise to cavitation and turbulence drag reduction technology, which uses natural or ventilated cavitation to fully or partially envelop the surface of the submersible to achieve drag reduction. This is one of the main benign applications of cavitation characteristics.

[0003] The application of cavitation and turbulence drag reduction technology to underwater vehicles can reduce resistance and increase navigation speed. Such underwater vehicles can perform patrol and attack missions in the ocean, greatly improving their rapid penetration and surprise attack capabilities.

[0004] The design of cavitation and turbulence drag reduction technology faces many challenges, especially when applied to large underwater vehicles of thousands of tons. The complex flow characteristics of cavitation and turbulent flow, such as multiphase, turbulence, phase change, and unsteadiness, place higher demands on the stability and maneuverability design of underwater vehicles. In particular, the high speed of ultra-high-speed underwater vehicles is achieved by wrapping the vehicle with supercavitation to reduce resistance. While supercavitation greatly reduces the fluid resistance of the vehicle, it also causes the vehicle to lose most of its buoyancy. Under this premise, how to achieve the navigation mechanical balance of the vehicle requires a reasonable design of its stable motion mode. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide a low-resistance ship design method for underwater vehicles, effectively cope with the complex flow characteristics such as multiphase, turbulence, phase change, and unsteady flow unique to cavitation and turbulent flow, and further meet the stability and maneuverability of underwater vehicles.

[0006] The technical solution of the present invention is to provide a low-resistance ship design method for an underwater vehicle, comprising:

[0007] S1: Preliminarily determine the basic geometric parameters of the underwater vehicle shape according to technical requirements;

[0008] S2: According to the characteristics of different types of line shapes, different parameter square polynomial line shape equations are selected to determine the head line shape equation and the tail line shape equation;

[0009] S3: according to the allowable value range of the adjustable parameters in the head line shape equation and the tail line shape equation and the influence of the change of the adjustable parameters on the line shape characteristics, the value of the adjustable parameters is determined to obtain the head preliminary line shape and the tail preliminary line shape;

[0010] S4: forming a preliminary underwater vehicle shape according to basic geometric parameters of the underwater vehicle shape and a preliminary line shape of the head and a preliminary line shape of the tail;

[0011] S5: Inspect the preliminary underwater vehicle shape, adjust the design parameters, and obtain the final vehicle shape that meets the technical requirements.

[0012] Furthermore, the basic geometric parameters in step S1 include the total length, head length, tail length, diameter, fin-rudder layout, and propeller parameters of the underwater vehicle.

[0013] Furthermore, the parameter square polynomial linear equation in step S2 is calculated by the following formulas:

[0014] (1) Two-parameter square polynomial circular linear equation

[0015] y 2 =r0R(x)+k s1 K s1 (x)+Q(x),0≤x≤1

[0016] (2) Two-parameter square root polynomial rounded linear equation

[0017]

[0018] (3) Single-parameter cubic polynomial flat-head linear equation

[0019]

[0020] (4) Single-parameter cubic root polynomial flat-end linear equation

[0021]

[0022] (5) Two-parameter square polynomial sharp head or sharp tail linear equation

[0023]

[0024] (6) Two-parameter general polynomial linear equation with pointed head or pointed tail

[0025]

[0026] Among them, x is the dimensionless parameter of the transverse coordinate, which is the ratio of the transverse coordinate of the head and tail to the length of the head and tail respectively; y is the dimensionless parameter of the longitudinal coordinate, which is the ratio of the longitudinal coordinate to the maximum radius of the underwater vehicle; r0 is the radius of curvature of the mathematical line type at x=0; R(x) is the influence function of r0; is the rate of change of curvature at x=1; K s1 (x) is The influence function of Q(x) is the linear other influence function; k s0 K is the curvature change rate at the intersection of the line and the front plane; s0 k s0 The influence function of ; s is the slope at x=0; S(x) is the influence function of s.

[0027] Furthermore, the influence function of each parameter square polynomial linear equation is in the form of:

[0028] (1) Two-parameter square polynomial circular linear equation, the specific expression is

[0029] y 2 =r0R(x)+k s1 K s1 (x)+Q(x)

[0030] R(x)=2x(x-1) 4

[0031]

[0032] Q(x)=1-(x-1) 4 (4x+1)

[0033] (2) Two-parameter square root polynomial round-end linear equation, the specific expression is:

[0034]

[0035] Q(x)=1-(x-1) 4

[0036] (3) Single-parameter cubic polynomial flat-head linear equation, the specific expression is

[0037]

[0038] Q(x)=x 2 (3x 2 -8x+6)

[0039] (4) Single-parameter cubic root polynomial flat-end linear equation, the specific expression is

[0040]

[0041] Q(x)=(x-1) 3 +1

[0042] (5) Two-parameter square polynomial pointed head or pointed tail linear equation, the specific expression is

[0043]

[0044] S(x)=x 2 (x-1) 4

[0045]

[0046] Q(x)=1-(x-1) 4 (10x 2 +4x+1)

[0047] (6) Two-parameter general polynomial pointed head or pointed tail linear equation, the specific expression is

[0048]

[0049] S(x)=x(x-1) 4

[0050]

[0051] Q(x)=1-(x-1) 4 (4x+1)

[0052] Furthermore, the head line shape equation adopts (5) a double-parameter square polynomial pointed head line shape or (6) a double-parameter general polynomial pointed head line shape, and the tail line shape equation adopts (5) a double-parameter square polynomial pointed tail line shape or (6) a double-parameter general polynomial pointed tail line shape; the adjustable parameters s, (4,10) or (3.5,8), the adjustable parameter s of the tail linear equation,

[0053] Further, the method for inspecting the preliminary underwater vehicle shape in step S5 includes:

[0054] Calculate the fullness of the underwater vehicle to check whether it meets the required volume requirements; calculate the surface pressure distribution of the underwater vehicle to check whether it meets the requirements of no cavitation under the given motion conditions of the underwater vehicle; calculate the boundary layer and drag coefficient of the flow to check its mechanical and noise performance;

[0055] If any inspection item does not meet the design requirements, the linear parameters and basic geometric parameters of the underwater vehicle shape are adjusted until the design requirements are met.

[0056] Furthermore, it also includes S6: experimentally confirming and iteratively improving the shape of the underwater vehicle designed through S1 to S5.

[0057] Furthermore, in step S6, the experimental confirmation method includes but is not limited to CFD method.

[0058] Furthermore, in the step S5, the inspection method is performed based on the experimental data obtained in the step S6, and the experimental data includes the pressure difference resistance and viscous resistance experienced by the underwater vehicle.

[0059] Furthermore, it is suitable for the low-resistance ship design of thousand-ton underwater vehicles.

[0060] The advantages of the present invention compared with the prior art are:

[0061] The present invention provides a low-resistance hull design method for underwater vehicles. Aiming at the low-resistance hull design of thousand-ton underwater vehicles, a specific linear equation is given, and the linear characteristics are optimized with adjustable parameters to form a complete vehicle shape. The overall performance simulation test is carried out through fluid mechanics software. This method can effectively cope with the complex flow characteristics such as multiphase, turbulence, phase change, and unsteady state unique to cavitation and turbulent flow, and further meet the design requirements such as stability and maneuverability of underwater vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 The present invention provides a method flow chart according to an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0064] like Figure 1 This is a flow chart of a low-resistance ship design method suitable for a thousand-ton underwater vehicle in a preferred embodiment of the present invention. The method comprises the following steps:

[0065] S1: Preliminarily determine the basic geometric parameters of the underwater vehicle shape according to technical requirements;

[0066] S2: According to the characteristics of different types of line shapes, different parameter square polynomial line shape equations are selected to determine the head line shape equation and the tail line shape equation;

[0067] S3: According to the allowable value range of the adjustable parameters in the basic equation of the line type and the influence of the change of the adjustable parameters on the line type characteristics, the value of the adjustable parameters is determined to obtain the preliminary line type of the head and the preliminary line type of the tail;

[0068] S4: forming a preliminary underwater vehicle shape according to basic geometric parameters of the underwater vehicle shape and a preliminary line shape of the head and a preliminary line shape of the tail;

[0069] S5: Check the preliminary underwater vehicle shape, adjust the design parameters, and obtain the final vehicle shape that meets the technical requirements;

[0070] S6: Experimentally confirm and iteratively improve the underwater vehicle shape obtained through S1 to S5.

[0071] In a preferred specific embodiment of the present invention, the basic geometric parameters in step S1 include the total length, head length, tail length, diameter, fin-rudder layout, and propeller parameters of the underwater vehicle.

[0072] In a preferred embodiment of the present invention, the parameter square polynomial linear equation calculation formulas in step S2 are:

[0073] (1) Two-parameter square polynomial circular linear equation

[0074] y 2 =r0R(x)+k s1 K s1 (x)+Q(x) (0≤x≤1)

[0075] (2) Two-parameter square root polynomial rounded linear equation

[0076]

[0077] (3) Single-parameter cubic polynomial flat-head linear equation

[0078]

[0079] (4) Single-parameter cubic root polynomial flat-end linear equation

[0080]

[0081] (5) Two-parameter square polynomial sharp head or sharp tail linear equation

[0082]

[0083] (6) Two-parameter general polynomial linear equation with pointed head or pointed tail

[0084]

[0085] Among them, x is the dimensionless parameter of the transverse coordinate, which is the ratio of the transverse coordinate of the head and tail to the length of the head and tail respectively; y is the dimensionless parameter of the longitudinal coordinate, which is the ratio of the longitudinal coordinate to the maximum radius of the underwater vehicle; r0 is the radius of curvature of the mathematical line type at x=0; R(x) is the influence function of r0; is the rate of change of curvature at x=1; K s1 (x) is The influence function of Q(x) is the linear other influence function; k s0 K is the curvature change rate at the intersection of the line and the front plane; s0 k s0 The influence function of ; s is the slope at x=0; S(x) is the influence function of s.

[0086] Preferably, the linear equation is as follows:

[0087] (1) Two-parameter square polynomial circular linear equation, its linear expression is

[0088] y 2 =r0R(x)+k s1 K s1 (x)+Q(x) (0≤x≤1)

[0089] R(x)=2x(x-1) 4

[0090]

[0091] Q(x)=1-(x-1) 4 (4x+1)

[0092] (2) Two-parameter square root polynomial round-end linear equation, its linear expression is

[0093]

[0094] Q(x)=1-(x-1) 4

[0095] (3) Single-parameter cubic polynomial flat-head linear equation, its linear expression is

[0096]

[0097] K s0 (x) = -6x(x-1) 3

[0098] Q(x)=x 2 (3x 2 -8x+6)

[0099] (4) Single-parameter cubic root polynomial flat-end linear equation, its linear expression is

[0100]

[0101] Q(x)=(x-1) 3 +1

[0102] (5) Two-parameter square polynomial pointed head or pointed tail linear equation, its linear expression is

[0103]

[0104] S(x)=x 2 (x-1) 4

[0105]

[0106] Q(x)=1-(x-1) 4 (10x 2 +4x+1)

[0107] (6) A two-parameter general polynomial linear equation with a pointed head or a pointed tail, whose linear expression is:

[0108]

[0109] S(x)=x(x-1) 4

[0110]

[0111] Q(x)=1-(x-1) 4 (4x+1)

[0112] Preferably, the head line shape equation adopts (5) a double-parameter square polynomial pointed head line shape or (6) a double-parameter general polynomial pointed head line shape, and the tail line shape equation adopts (5) a double-parameter square polynomial pointed tail line shape or (6) a double-parameter general polynomial pointed tail line shape; in step S3, the adjustable parameters s and k of the head line shape equation are s1 =(3,10), (4,10) or (3.5,8), the adjustable parameters s and k of the tail linear equation s1 =(2,12), (2,20) or (3,15).

[0113] In a preferred specific embodiment of the present invention, the head and tail line shapes of the underwater vehicle in step S4 are provided by the optimal line shapes obtained by the expression of step S3, and the obtained head preliminary line shape and tail preliminary line shape are used to form a complete preliminary underwater vehicle shape.

[0114] In a preferred specific embodiment of the present invention, the method for inspecting the preliminary underwater vehicle shape in step S5 includes: calculating the fullness of the underwater vehicle to inspect whether the required volume requirement is met; calculating the surface pressure distribution of the underwater vehicle to inspect whether the cavitation-free requirement is met under the given motion conditions of the underwater vehicle; calculating the flow boundary layer and the drag coefficient to inspect its mechanical and noise performance;

[0115] If any inspection item does not meet the design requirements, the linear parameters and basic geometric parameters of the underwater vehicle shape are adjusted until the design requirements are met.

[0116] In a preferred embodiment of the present invention, in step S6, the experimental confirmation method includes but is not limited to the CFD method.

[0117] In a preferred specific embodiment of the present invention, in step S5, the inspection method is performed based on the experimental data obtained in step S6, and the experimental inspection data includes the pressure difference resistance and viscous resistance experienced by the underwater vehicle.

[0118] In a preferred specific embodiment of the present invention, in step S6, the modification and improvement of the underwater vehicle is based on experiments. By controlling key points, based on the preliminary shape of the underwater vehicle, by adjusting the lengths of the front and rear underwater vehicles and combining the line type formula described in step S3, the head and tail line types are determined to achieve the purpose of optimizing the design.

[0119] It is to be understood that the present invention is described by way of embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and embodiments that can fall within the scope of the claims of this application all fall within the scope protected by the present invention.

[0120] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for designing a low-resistance underwater vehicle, characterized in that: According to the technical requirements, the basic geometric parameters of the underwater vehicle shape are preliminarily determined; According to the characteristics of different types of lines, square polynomial line equations with different parameters are selected to determine the head line equation and the tail line equation; According to the allowable value range of the adjustable parameters in the head line shape equation and the tail line shape equation and the influence of the change of the adjustable parameters on the line shape characteristics, the value of the adjustable parameters is determined to obtain the head preliminary line shape and the tail preliminary line shape; According to the basic geometric parameters of the underwater vehicle shape and the preliminary line shape of the head and the preliminary line shape of the tail, a preliminary underwater vehicle shape is formed; The preliminary underwater vehicle shape is inspected and the design parameters are adjusted to obtain the final underwater vehicle shape that meets the technical requirements.

2. The method for designing a low-resistance underwater vehicle according to claim 1, characterized in that: The basic geometric parameters of the underwater vehicle's shape include the underwater vehicle's total length, head length, tail length, diameter, fin and rudder layout, and propeller parameters.

3. The method for designing a low-resistance underwater vehicle according to claim 1, characterized in that: The square polynomial linear equations of each parameter are calculated by the following formulas: (1) Two-parameter square polynomial circular linear equation y 2 =r0R(x)+k s1 K s1 (x)+Q(x),0≤x≤1 (2) Two-parameter square root polynomial rounded linear equation (3) Single-parameter cubic polynomial flat-head linear equation (4) Single-parameter cubic root polynomial flat-end linear equation (5) Two-parameter square polynomial sharp head or sharp tail linear equation (6) Two-parameter general polynomial linear equation with pointed head or pointed tail Among them, x is the dimensionless parameter of the transverse coordinate, which is the ratio of the transverse coordinate of the head and tail to the length of the head and tail respectively; y is the dimensionless parameter of the longitudinal coordinate, which is the ratio of the longitudinal coordinate to the maximum radius of the underwater vehicle; r0 is the radius of curvature of the mathematical line type at x=0; R(x) is the influence function of r0; is the rate of change of curvature at x=1; K s1 (x) is The influence function of Q(x) is the linear other influence function; k s0 K is the curvature change rate at the intersection of the line and the front plane; s0 k s0 The influence function of ; s is the slope at x=0; S(x) is the influence function of s.

4. The method for designing a low-resistance underwater vehicle according to claim 3, characterized in that: (1) Two-parameter square polynomial circular linear equation, the specific expression is y 2 =r0R(x)+k s1 K s1 (x)+Q(x) R(x)=2x(x-1) 4 Q(x)=1-(x-1) 4 (4x+1) (2) Two-parameter square root polynomial round-end linear equation, the specific expression is: Q(x)=1-(x-1) 4 (3) Single-parameter cubic polynomial flat-head linear equation, the specific expression is Q(x)=x 2 (3x 2 -8x+6) (4) Single-parameter cubic root polynomial flat-end linear equation, the specific expression is Q(x)=(x-1) 3 +1 (5) Two-parameter square polynomial pointed head or pointed tail linear equation, the specific expression is S(x)=x 2 (x-1) 4 Q(x)=1-(x-1) 4 (10x 2 +4x+1) (6) Two-parameter general polynomial pointed head or pointed tail linear equation, the specific expression is S(x)=x(x-1) 4 Q(x)=1-(x-1) 4 (4x+1) 5. The method for designing a low-resistance underwater vehicle according to claim 4, characterized in that: The head line shape equation adopts a double-parameter square polynomial pointed head line shape or a double-parameter general polynomial pointed head line shape, and the tail line shape equation adopts a double-parameter square polynomial pointed tail line shape or a double-parameter general polynomial pointed tail line shape; the adjustable parameters s, (4,10) or (3.5,8), the adjustable parameter s of the tail linear equation, (2,20) or (3,15).

6. The method for designing a low-resistance underwater vehicle according to claim 1, characterized in that: The method for checking the preliminary underwater vehicle shape includes: Calculate the fullness of the underwater vehicle to check whether it meets the required volume requirements; calculate the surface pressure distribution of the underwater vehicle to check whether it meets the requirements of no cavitation under the given motion conditions of the underwater vehicle; calculate the boundary layer and drag coefficient of the flow to check its mechanical and noise performance; If any inspection item does not meet the design requirements, the linear parameters and basic geometric parameters of the underwater vehicle shape are adjusted until the design requirements are met.

7. The method for designing a low-resistance underwater vehicle according to claim 6, characterized in that: After obtaining the final underwater navigation shape that meets the technical requirements, the method further includes the steps of: experimentally confirming and iteratively improving the final underwater navigation shape.

8. The method for designing a low-resistance underwater vehicle according to claim 7, characterized in that: Experimental confirmation methods include but are not limited to CFD methods.

9. The method for designing a low-resistance underwater vehicle according to claim 7, characterized in that: The inspection method for inspecting the preliminary underwater vehicle shape is carried out on the basis of experimental data obtained through experimental confirmation, and the experimental data include the pressure difference resistance and viscous resistance experienced by the underwater vehicle.

10. The method for designing a low-resistance underwater vehicle according to any one of claims 1 to 9, characterized in that: Suitable for low-resistance ship design of thousand-ton underwater vehicles.

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