Rectifier plate for fixing the lower end of underwater vehicle rudder and design method and system thereof

Abstract

The present invention discloses a rectifier plate for fixing to the lower end of an underwater vehicle's rudder, and a design method and system thereof. The method comprises: determining the rectifier plate installation position and preliminarily determining the top-view shape and size of the rectifier plate; establishing a three-dimensional model of the underwater vehicle and rudder, using CFD (computational fluid dynamics) methods to determine the flow field and streamline shape near the rectifier plate installation position, and determining the side profile shape of the rectifier plate; optimizing the rectifier plate parameters; performing hydrodynamic analysis on numerical calculation models of the underwater vehicle, rudder, and propeller, and determining the final design of the rectifier plate based on multiple indicators. By fixing the rectifier plate to the lower end of the underwater vehicle's rudder, the phenomenon of flow around the lower end face of the rudder can be effectively suppressed, reducing lateral flow of the rudder, thereby reducing fluid turbulence and improving the lift and efficiency of the rudder. The presence of the rectifier plate avoids circulation loss, which is equivalent to increasing the aspect ratio of the rudder, improving the lift of the rudder, and significantly improving the rudder efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater vehicle maneuverability, and in particular to a rectifier plate for fixing the lower end of a rudder of an underwater vehicle, and a design method and system thereof. Background Art

[0002] The two main warships of modern navies are surface ships and submarines. Due to the unique operational environment and requirements of submarines, maneuverability and stealth are crucial. Submarines primarily rely on rudders to achieve horizontal turning and vertical submergence and surfacing. The rudder operates by applying hydrodynamic forces to the rudder, generating vertical or lateral forces perpendicular to the hull, thereby achieving motion. Therefore, rudder performance directly impacts submarine maneuverability. However, traditional rudder designs have inherent challenges, particularly during high-speed navigation and maneuvering.

[0003] Currently, submarine rudders typically employ a design similar to a low-aspect-ratio wing. This makes the rudder susceptible to lateral flow during operation, leading to strong lateral flow around the rudder tip. This flow not only reduces the velocity circulation along the rudder's chord length, reducing the effective angle of attack, but also increases induced drag, adversely affecting the rudder's lift and efficiency. Furthermore, during straight-line navigation, the influence of ocean currents and steering clearances requires an automatic control system to adjust the rudder angle within a small range to maintain a straight-line state. This means that the rudder angle is not always zero during straight-line navigation, but rather fluctuates within a small range, further increasing the complexity of the rudder's operation.

[0004] In the existing technical solutions, due to the existence of the rudder angle, the gap between the lower end surface of the rudder and the lower fixed wing will be significantly increased. At the same time, there will be a certain pressure difference on the two sides of the rudder, which will cause the fluid on the lower end surface of the rudder to flip and form a strong vortex, causing the rudder to vibrate and increase the noise of the rudder. In addition, the vibration noise of the underwater vehicle mostly comes from the stern, mainly including mechanical noise, propulsion noise and hydrodynamic noise, among which the propeller hydrodynamic noise is particularly serious. Due to the unevenness of the flow field at the propeller disk, the lateral flow generated by the underwater vehicle rudder and the vortex formed by the fluid flipping will cause turbulence in the flow field behind the rudder, increase the unevenness of the flow field at the propeller disk, aggravate the propeller vibration and noise, reduce the propeller propulsion efficiency, and have an adverse effect on the stealth and speed of the submarine. These problems are exactly the key issues that the present invention aims to solve. Summary of the Invention

[0005] In response to the above-mentioned deficiencies or improvements in the prior art, the present invention aims to provide a flow straightener for fixing the lower end of an underwater vehicle's rudder, as well as a design method and system thereof. By installing and fixing the flow straightener at the lower end of an underwater vehicle's rudder, the flow straightener can effectively suppress flow around the lower end face of the rudder, reduce lateral flow around the rudder, and prevent the formation of separation vortices caused by fluid inversion at small rudder angles, thereby reducing fluid turbulence and improving the rudder's lift and efficiency. The presence of the flow straightener avoids circulation loss, which is equivalent to increasing the rudder's aspect ratio, improving the rudder's lift and reducing induced drag without increasing overall drag, thereby significantly improving rudder efficiency. Because the flow straightener suppresses flow around the rudder end, it reduces turbulence in the flow field behind the rudder, making the flow field behind the rudder more uniform and minimizing its impact on the propeller disc flow field. This stabilizes the propeller's motion environment, reduces propeller excitation forces and noise, and thereby improves the propeller's propulsion efficiency and helps extend its service life.

[0006] According to a first aspect of the present invention, there is provided a method for designing a fixed fairing plate at the lower end of a rudder of an underwater vehicle, comprising:

[0007] S100, determining the installation position of the rectifier plate according to the installation position of the rudder of the underwater vehicle, and preliminarily determining the top view shape and size of the rectifier plate;

[0008] S200, establishing a three-dimensional model of the underwater vehicle and the rudder, using a CFD (computational fluid dynamics) method to determine the flow field and streamline shape near the installation position of the rectifier, and determining the side shape of the rectifier based on the flow field and streamline shape;

[0009] S300, with the goal of suppressing the flow around the rudder end, considering the influence of the fairing on the rudder lift and drag, using the CFD method to optimize the installation position, top view shape, size, and side profile of the fairing, determine a preliminary design scheme for the fairing, and optimize the fairing parameters with reference to the flow field uniformity of the propeller disk of the underwater vehicle;

[0010] S400, considering the interference of the suction effect of the underwater vehicle propeller on the flow field around the rectifier, establishing a numerical calculation model of the underwater vehicle, the rudder, and the propeller, evaluating the influence of the propeller on the rectifier, and adjusting the rectifier parameters;

[0011] S500: Perform hydrodynamic analysis on the numerical calculation models of the underwater vehicle, rudder, and propeller, and determine the final design of the rectifier in combination with maneuverability, speed, and stealth indicators.

[0012] Furthermore, step S100 includes:

[0013] S101. Determine the relative position of the straightening plate on the vehicle based on the installation position of the rudder and the clearance between the straightening plate and other components of the vehicle, and fine-tune the installation position and angle of the straightening plate based on flow field characteristics.

[0014] S102. Determine the top view shape of the rectifier plate according to the design requirements, and preliminarily estimate the size of the rectifier plate according to relevant specifications or empirical formulas, and adjust and optimize it in the subsequent process;

[0015] Furthermore, step S200 includes:

[0016] S201, using three-dimensional modeling software to establish a model of the underwater vehicle and rudder, and performing grid division on the model;

[0017] S202. Import the data into professional CFD software, set boundary conditions according to actual working conditions, run CFD simulation, monitor the convergence and stability of the simulation process, and analyze the flow field and streamline shape at the rectifier installation location;

[0018] S203 : Determine the side shape of the rectifier plate according to the flow field and streamline shape at the installation position of the rectifier plate.

[0019] Furthermore, step S201 includes: appropriately simplifying the model according to the needs of the CFD simulation, and removing details that have little impact on the fluid flow.

[0020] Furthermore, step S300 includes:

[0021] S301. Based on experience and preliminary simulation results, design preliminary solutions for rectifiers with various geometric parameters. Evaluate the effects of the rectifiers on the lift and drag of the rudder according to steps S201-S202. After each calculation converges, continuously adjust the rectifier parameters based on the simulation results to find the optimal solution.

[0022] S302. Adjust the parameters of the master rectifier plate to examine the effect of different parameters on the flow field uniformity of the propeller disc. Compare the flow field uniformity of the propeller disc after the master rectifier plate is optimized with that of the original propeller disc to evaluate the improvement effect.

[0023] Furthermore, step S400 includes:

[0024] S401. On the basis of step S301, according to the specific parameters and layout of the propeller, the corresponding propeller is added to the model to establish a numerical calculation model of the underwater vehicle, rudder, fairing, and propeller.

[0025] S402. Use a CFD solver to solve the numerical calculation model to obtain detailed flow information of the flow field around the rectifier, analyze the specific impact of the propeller suction effect on the flow field around the rectifier, and evaluate the potential impact of these impacts on the performance of the rectifier.

[0026] S403. Based on the numerical simulation results, identify the key parameters that have a significant impact on the performance of the rectifier plate, make preliminary adjustments to the key parameters, and re-perform numerical simulation to evaluate the adjustment effect. Perform numerical simulation verification on the optimized rectifier plate to ensure that it can minimize the impact of the thruster's suction effect while meeting the design requirements.

[0027] According to the second aspect of the present invention, there is provided a fixing straightening plate for the lower end of the rudder of an underwater vehicle, which is realized by applying the above-mentioned design method for fixing the straightening plate for the lower end of the rudder of an underwater vehicle. The straightening plate can effectively suppress the flow around the lower end face of the rudder of the underwater vehicle, reduce the lateral flow of the rudder, and prevent the fluid from flipping over at the rudder end to form a separation vortex when the rudder angle is small; the straightening plate is arranged in the gap between the rear end of the stabilizing wing and the rotating rudder, and is installed on the upper end face of the stabilizing wing. The plane is perpendicular to the rudder surface, and the side shape is the same as the streamline shape at the installation position.

[0028] Furthermore, the top view shape of the straightening plate can be changed accordingly according to the flow field near the rudder.

[0029] Furthermore, the top view shape of the fairing can adopt a specific airfoil profile or be the same as the rudder wing profile to maximize the benefits of the fairing.

[0030] According to a third aspect of the present invention, there is provided a system for designing a fixed fairing at the lower end of a rudder of an underwater vehicle, comprising:

[0031] The first module determines the installation position of the fairing according to the rudder installation position of the underwater vehicle, and preliminarily determines the top view shape and size of the fairing;

[0032] The second module establishes a three-dimensional model of the underwater vehicle and the rudder, uses computational fluid dynamics methods to determine the flow field and streamline shape near the installation position of the rectifier, and determines the side shape of the rectifier based on the flow field and streamline shape;

[0033] The third module aims to suppress the flow around the rudder end, taking into account the influence of the fairing on the rudder lift and drag. Computational fluid dynamics methods are used to optimize the installation position, top view shape, size, and side profile of the fairing. The preliminary design scheme of the fairing is determined, and the fairing parameters are optimized with reference to the uniformity of the flow field on the propeller disk of the underwater vehicle.

[0034] The fourth module considers the interference of the suction effect of the underwater vehicle propeller on the flow field around the rectifier, establishes a numerical calculation model of the underwater vehicle, rudder, and propeller, evaluates the impact of the propeller on the rectifier, and adjusts the rectifier parameters;

[0035] The fifth module conducts hydrodynamic analysis on the numerical calculation models of the underwater vehicle, rudder and propeller, and determines the final design scheme of the fairing based on the maneuverability, speed and stealth indicators.

[0036] Beneficial effects of the present invention:

[0037] 1. The rectifying plate proposed in the present invention can be fixed on the lower end of the rudder of the underwater vehicle, which can effectively suppress the flow around the lower end face of the rudder, reduce the lateral flow of the rudder, and prevent the fluid from flipping and forming a separation vortex at a small rudder angle, thereby reducing fluid turbulence and improving the lift and efficiency of the rudder. The presence of the rectifying plate avoids circulation loss, which is equivalent to increasing the aspect ratio of the rudder, improving the lift of the rudder, and reducing the induced drag without increasing the overall drag, thereby significantly improving the rudder efficiency. Since the rectifying plate can suppress the flow around the rudder end and reduce the turbulence of the flow field behind the rudder, the flow field behind the rudder becomes more uniform, thereby reducing the impact on the propeller disc flow field. The propeller movement environment becomes more stable, the propeller excitation force and noise are reduced, thereby improving the propulsion efficiency of the propeller, and also helping to extend the service life of the propeller.

[0038] 2. The proposed rectifier design method improves the uniformity of the flow field at the propeller disk by optimizing the rectifier design, reducing propeller excitation forces and radiated noise, thereby enhancing the stealth of underwater vehicles. Furthermore, because the rectifier provides a stabilizing torque, it helps maintain the stability of the underwater vehicle, reducing unnecessary rudder movements and improving navigation speed and stability.

[0039] 3. The rectifier plate proposed in this invention has a simple structure and is easy to install. Its design can flexibly adapt to the needs of different rudder types. It can be integrated during the design phase or designed and installed on existing rudders. This is an effective remedial measure for defective rudders. In summary, through the rational design of the rectifier plate, this invention achieves comprehensive improvements in the maneuverability, stealth, and propulsion efficiency of underwater vehicles.

[0040] Additional aspects and advantages of the present application will be given in part in the following description, which will become apparent from the following description, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0042] Figure 1 This is a flow chart of a method for designing a rectifier plate for fixing the lower end of a rudder of an underwater vehicle according to an embodiment of the present invention;

[0043] Figure 2 This is a vortex distribution cloud diagram at the propeller disk surface of the end plate-free solution in an embodiment of the present invention;

[0044] Figure 3 This is a vortex distribution cloud diagram of the end plate at the propeller disk surface in the first embodiment of the present invention;

[0045] Figure 4 This is a vortex distribution cloud diagram of the end plate at the propeller disk surface in the second embodiment of the present invention;

[0046] Figure 5 This is a vortex distribution cloud diagram of the third end plate at the propeller disk surface in the embodiment of the present invention;

[0047] Figure 6 This is a vortex distribution cloud diagram of the end plate of the fourth embodiment of the present invention at the propeller disk surface;

[0048] Figure 7 This is a cloud diagram of the axial velocity distribution at the propeller disk surface of the end plate-free solution in an embodiment of the present invention;

[0049] Figure 8 This is a cloud diagram of the axial velocity distribution of the end plate at the propeller disk surface in the first embodiment of the present invention;

[0050] Figure 9 This is a cloud diagram of the axial velocity distribution of the end plate at the propeller disk surface in the second embodiment of the present invention;

[0051] Figure 10 This is a cloud diagram of the axial velocity distribution of the third end plate at the propeller disk surface in the embodiment of the present invention;

[0052] Figure 11 This is a cloud diagram of the axial velocity distribution of the end plate at the propeller disk surface in the fourth embodiment of the present invention;

[0053] Figure 12 This is a cloud diagram of the circumferential velocity distribution at the propeller disk surface of the end plate-free solution in an embodiment of the present invention;

[0054] Figure 13 This is a cloud diagram of the circumferential velocity distribution of the end plate at the propeller disk surface in the first embodiment of the present invention;

[0055] Figure 14 This is a cloud diagram of the circumferential velocity distribution of the end plate at the propeller disk surface in the second embodiment of the present invention;

[0056] Figure 15 This is a cloud diagram of the circumferential velocity distribution of the third end plate at the propeller disk surface in the embodiment of the present invention;

[0057] Figure 16 This is a cloud diagram of the circumferential velocity distribution of the end plate of the fourth embodiment of the present invention at the propeller disk surface;

[0058] Figure 17 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.37m in the embodiment of the present invention;

[0059] Figure 18 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.39m in the embodiment of the present invention;

[0060] Figure 19 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.40m in the embodiment of the present invention;

[0061] Figure 20 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.41m in the embodiment of the present invention;

[0062] Figure 21 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.42m in the embodiment of the present invention;

[0063] Figure 22 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.43m in the embodiment of the present invention;

[0064] Figure 23 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.44m in the embodiment of the present invention;

[0065] Figure 24 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.45m in the embodiment of the present invention;

[0066] Figure 25 : is a comparison diagram of the axial velocity distribution of various schemes at a radius of R = 0.47m in the embodiment of the present invention;

[0067] Figure 26 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.37m in the embodiment of the present invention;

[0068] Figure 27 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.39m in the embodiment of the present invention;

[0069] Figure 28 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.40m in the embodiment of the present invention;

[0070] Figure 29 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.41m in the embodiment of the present invention;

[0071] Figure 30 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.42m in the embodiment of the present invention;

[0072] Figure 31 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.43m in the embodiment of the present invention;

[0073] Figure 32 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.44m in the embodiment of the present invention;

[0074] Figure 33 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.45m in the embodiment of the present invention;

[0075] Figure 34 : is a comparison diagram of the circumferential velocity distribution of various schemes at a radius of R = 0.47m in the embodiment of the present invention;

[0076] Figure 35 Schematic diagram of the geometric shape of a conventional rudder of an underwater vehicle in an embodiment of the present invention;

[0077] Figure 36 Schematic diagram of the geometric shape of the underwater vehicle rudder with a fairing in an embodiment of the present invention;

[0078] Figure 37 This is a schematic diagram of the streamline shape of the lower end surface of the rudder of an underwater vehicle with a straightening plate in an embodiment of the present invention.

[0079] Figure 38 This is a schematic diagram of the geometric shape of the underwater vehicle rudder with a straightening plate according to the embodiment of the present invention.

[0080] Figure 39 This is a schematic diagram of the geometric shape of the underwater vehicle rudder with the second solution rectifier in the embodiment of the present invention.

[0081] Figure 40 2. This is a schematic diagram of the geometric shape of the underwater vehicle rudder with the third solution rectifier added in an embodiment of the present invention;

[0082] Figure 41 Schematic diagram of the geometric shape of the underwater vehicle rudder with the fourth rectifier plate in the embodiment of the present invention. DETAILED DESCRIPTION

[0083] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0084] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a," "an," "said," and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the stated features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0085] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless specifically defined as in the examples of this application.

[0086] The present invention provides a flow straightener for securing the underside of an underwater vehicle's rudder, as well as a design method and system. By installing and securing the flow straightener at the underside of an underwater vehicle's rudder, the flow straightener effectively suppresses flow around the underside of the rudder, reduces lateral flow around the rudder, and prevents flow inversion and separation vortex formation at small rudder angles, thereby reducing flow turbulence and improving the rudder's lift and efficiency. The flow straightener avoids circulation loss, effectively increasing the rudder's aspect ratio, improving its lift and reducing induced drag without increasing overall drag, significantly improving rudder efficiency. Because the flow straightener suppresses flow around the rudder end, it reduces turbulence in the flow field behind the rudder, making the flow field behind the rudder more uniform and minimizing its impact on the propeller's disc flow field. This stabilizes the propeller's motion environment, reduces propeller excitation force and noise, and thereby improves propeller propulsion efficiency and extends its service life. By optimizing the flow straightener design, the uniformity of the flow field at the propeller disc can be improved, reducing propeller excitation force and radiated noise, thereby enhancing the underwater vehicle's stealth. In addition, since the rectifier provides a stable torque, it can help maintain the navigation stability of the underwater vehicle, reduce unnecessary rudder movements, and help improve navigation speed and stability.

[0087] Example 1:

[0088] like Figure 1 As shown, an embodiment of the present invention provides a method for designing a rectifier plate for fixing the lower end of a rudder of an underwater vehicle, comprising:

[0089] S100, determining the installation position of the rectifier plate according to the installation position of the rudder of the underwater vehicle, and preliminarily determining the top view shape and size of the rectifier plate;

[0090] Step S100 specifically includes:

[0091] S101. The installation position of the fairing is mainly determined by the installation position of the rudder and the flow field characteristics. The installation position of the fairing should be close to the lower end of the rudder to improve the flow field characteristics near the rudder. According to the installation position of the rudder, the relative position of the fairing on the vehicle is determined. The fairing should be parallel to the rudder surface and located near the lower edge of the rudder. At the same time, the gap between the fairing and other parts of the vehicle (such as the tail structure, propeller, etc.) is considered to ensure that there is no mutual interference. At the same time, according to the flow field characteristics, the installation position and angle of the fairing are fine-tuned to minimize resistance and improve stability.

[0092] S102. While the shape of the rectifier may vary depending on design requirements, a rectangular shape is generally used. The primary function of the rectifier is to straighten the water flow through the rudder surface, reducing turbulence and eddies, thereby improving rudder efficiency and the submarine's navigation performance. The rectangular shape can better adapt to changes in the direction and speed of the fluid, achieving this goal. Furthermore, the rectangular structure offers good mechanical stability, resisting fluid impact and vibration, maintaining the balance and stability of the rudder surface. If the rudder uses an asymmetric airfoil, the rectifier should also be designed with an asymmetric shape to match the rudder's flow field characteristics.

[0093] S103. The width b of the rectifier is a key parameter that directly affects the rectifier's performance. A preliminary estimate can be made by referring to relevant specifications or empirical formulas. The optimal ratio of the rectifier's width to the rudder's chord length is 0.07. This preliminary estimate of width b should serve as a starting point for subsequent design and simulation, and should be adjusted and optimized as needed.

[0094] S200, establishing a three-dimensional model of the underwater vehicle and the rudder, using a CFD (computational fluid dynamics) method to determine the flow field and streamline shape near the installation position of the rectifier, and determining the side shape of the rectifier based on the flow field and streamline shape;

[0095] Step S200 specifically includes:

[0096] S201. Use 3D modeling software (such as SolidWorks or Catia) to create a model of the underwater vehicle and rudder. The model should be highly accurate and accurately reflect the size and shape of the vehicle and the position and size of the rudder. The model can be appropriately simplified to remove details that have little impact on fluid flow, as required by the CFD simulation.

[0097] S202. Use CFD pre-processing software to mesh the model. Mesh quality is crucial to the accuracy and efficiency of CFD calculations, so ensure that the mesh has sufficient density and resolution at the rectifier mounting locations. The mesh type can be structured or unstructured, depending on the complexity of the model and computing resources. For areas with complex shapes, local mesh refinement can be used to improve calculation accuracy.

[0098] S203. Import the mesh into professional CFD software (such as ANSYS Fluent or STAR-CCM+) capable of handling complex flow problems. After importing, set boundary conditions based on the actual operating conditions. Run the CFD simulation, monitoring convergence and stability to ensure reliable results. Analyze the flow field and streamline shape at the rectifier installation location, focusing on velocity vector distribution and vortex distribution.

[0099] S204. Design the side shape of the rectifier according to the streamline shape obtained by CFD simulation. In step S102, it has been preliminarily determined that the shape of the rectifier is rectangular, so only the two shapes of the end plate cross section, "I" shape or "[" shape, are considered here.

[0100] S300, with the goal of suppressing the flow around the rudder end, considering the influence of the fairing on the rudder lift and drag, using the CFD method to optimize the installation position, top view shape, size, and side profile of the fairing, determine a preliminary design scheme for the fairing, and optimize the fairing parameters with reference to the flow field uniformity of the propeller disk of the underwater vehicle;

[0101] Step S300 specifically includes:

[0102] S301. Based on experience and preliminary simulation results, design preliminary solutions for several rectifier plates with different geometric parameters.

[0103] S302. Evaluate the effect of the rectifier on the lift and drag of the rudder according to steps S201-S203. After each calculation converges, continuously adjust the parameters of the rectifier, such as the installation position, width, and thickness distribution, based on the simulation results to find the optimal solution. This rectifier can be used as the mother rectifier for subsequent optimization.

[0104] S303. Analyze the flow field uniformity of the propeller disc of the underwater vehicle to understand its impact on navigation performance. Adjust the parameters of the parent rectifier to examine their impact on the propeller disc's flow field uniformity. Compare the flow field uniformity of the propeller disc after optimizing the parent rectifier with that of the original propeller disc to evaluate the improvement.

[0105] S400, considering the interference of the suction effect of the underwater vehicle propeller on the flow field around the rectifier, establishing a numerical calculation model of the underwater vehicle, the rudder, and the propeller, evaluating the influence of the propeller on the rectifier, and adjusting the rectifier parameters;

[0106] Step S400 specifically includes:

[0107] S401. On the basis of step S302, according to the specific parameters and layout of the propeller, the corresponding propeller is added to the model to establish a numerical calculation model of the underwater vehicle, rudder, fairing, and propeller.

[0108] S402. Use a CFD solver to solve the established numerical calculation model to obtain detailed flow information about the flow field around the rectifier. Focus on flow parameters such as pressure distribution, velocity vector, and vortex distribution before and after the rectifier. Analyze the specific effects of the propeller suction on the flow field around the rectifier, including pressure difference, flow velocity changes, vortex generation and shedding, and evaluate the potential impact of these effects on the rectifier's performance (such as resistance and stability).

[0109] S403. Based on the numerical simulation results, identify key parameters that significantly impact the performance of the rectifier (e.g., rectifier position, shape, and size). Initially adjust these key parameters and re-run the numerical simulation to evaluate the effectiveness of the adjustments. Perform numerical simulation verification on the optimized rectifier to ensure that it meets design requirements while minimizing the impact of the thruster's suction.

[0110] S500: Perform hydrodynamic analysis on the numerical calculation models of the underwater vehicle, rudder, and propeller, and determine the final design of the rectifier in combination with maneuverability, speed, and stealth indicators.

[0111] Example 2:

[0112] like Figure 35 As shown in the figure, when an underwater vehicle is sailing straight, due to the influence of ocean currents and steering clearance, the rudder angle is automatically adjusted within a small range to maintain straightness. Therefore, the rudder angle is not always at 0° during straight sailing, but varies slightly. At a certain rudder angle, the gap between the lower end surface of the rudder and the fixed wing below will increase significantly. At the same time, due to the rudder angle, a certain pressure difference will exist between the two sides of the rudder, causing the fluid to flip at the lower end surface of the rudder, forming a strong vortex. The vortex flows backward toward the rotor disk of the pump-jet propeller, resulting in greater circumferential unevenness of the flow field on the rotor disk, thereby increasing the propeller's excitation force and radiated noise.

[0113] like Figure 36To address the aforementioned issues, based on Example 1, this embodiment proposes a fixed straightening plate at the lower end of an underwater vehicle's rudder. This plate is used to reduce fluid turbulence caused by excessive clearance at the lower end of the rudder, thereby reducing the uneven flow field at the rotor disk and minimizing the propeller's excitation force and radiated noise. The straightening plate is installed in the gap between the rear end of a conventional rudder stabilizer and the rotating rudder of the underwater vehicle, and a fixed plate is additionally installed on the upper end of the stabilizer.

[0114] like Figure 37 As shown in Figure 1, a certain actual model is taken as the research object, and a grid calculation model of the overall structure of the hull and rudder is established. The flow field around the hull is calculated under the navigation condition of Vs = 12 kn, n = 500 rpm (Vs is the speed of the underwater vehicle, and n is the propeller speed). The shape of the streamline near the lower end surface of the rudder is obtained. The vertical coordinates of the streamline at each longitudinal position are shown in Table 1, where x = 16.763 is the longitudinal coordinate of the starting point of the streamline, and x = 17.352 is the coordinate at the trailing edge of the rudder.

[0115] Table 1

[0116] x y z 1 16.763 0.676 0.1 2 17.062 0.62 0.04 3 17.352 0.559 0.005

[0117] Therefore, the line connecting the two points (16.763, 0.676, 0) and (17.352, 0.559, 0) is taken as the end plate generatrix of the end plate at the lower end face of the rudder.

[0118] like Figures 38-41 As shown, this embodiment proposes four rectifier end plate solutions, and the main technical parameters of the end plates are shown in Table 2.

[0119] Table 2

[0120]

[0121] In order to consider the influence of the end plate on the flow field of the rotor disk, only the calculation grid of the hull-rudder (end plate) is established during the calculation. The rudder angle of each scheme is 3°. The vortex distribution cloud diagrams at the propeller disk surface of the scheme without end plate and the four schemes with end plate are calculated, as shown in the following figure: Figure 2-Figure 6 As shown in the figure, the original scheme without end plates forms an obvious concentrated vortex in the flow field area inside the propeller, and the vortex intensity is relatively strong, while the four end plate schemes can better suppress the concentrated vortex and the vortex intensity is significantly reduced.

[0122] The axial velocity of the original scheme without end plates and the scheme with four end plates at the propeller disk surface is as follows: Figure 7-12 As shown, the circumferential velocity cloud distribution is as follows Figures 13-18 As shown, it can be understood that since the concentrated vortex of the original scheme is stronger, the wake peak values ​​of the axial and circumferential velocities are higher, while the four end plate schemes can all reduce the wake peak values ​​to varying degrees.

[0123] In order to specifically analyze the impact of the original no-end-plate scheme and the four-end-plate scheme on the internal flow field of the propeller, this embodiment established a hull-rudder-propeller overall structure grid for numerical calculation, and analyzed and compared the axial velocity and circumferential velocity distribution curves of the pump jet flow field at different radii on the propeller disc surface. The comparison of the axial velocity distribution at different radii of the propeller disc surface of each scheme is shown in the figure below. Figures 17-25 As shown, the circumferential velocity distribution is compared as shown in 26- Figure 34 shown.

[0124] Example 3:

[0125] This embodiment provides a design system for fixing a fairing plate at the lower end of a rudder of an underwater vehicle, comprising:

[0126] The first module determines the installation position of the fairing according to the rudder installation position of the underwater vehicle, and preliminarily determines the top view shape and size of the fairing;

[0127] The second module establishes a three-dimensional model of the underwater vehicle and the rudder, uses computational fluid dynamics methods to determine the flow field and streamline shape near the installation position of the rectifier, and determines the side shape of the rectifier based on the flow field and streamline shape;

[0128] The third module aims to suppress the flow around the rudder end, taking into account the influence of the fairing on the rudder lift and drag. Computational fluid dynamics methods are used to optimize the installation position, top view shape, size, and side profile of the fairing. The preliminary design scheme of the fairing is determined, and the fairing parameters are optimized with reference to the uniformity of the flow field on the propeller disk of the underwater vehicle.

[0129] The fourth module considers the interference of the suction effect of the underwater vehicle propeller on the flow field around the rectifier, establishes a numerical calculation model of the underwater vehicle, rudder, and propeller, evaluates the impact of the propeller on the rectifier, and adjusts the rectifier parameters;

[0130] The fifth module conducts hydrodynamic analysis on the numerical calculation models of the underwater vehicle, rudder and propeller, and determines the final design scheme of the fairing based on the maneuverability, speed and stealth indicators.

[0131] It should be understood that although the steps in the flowcharts of the accompanying drawings are shown in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the flowcharts of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0132] The above description is only part of the implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A design method for fixing a rectifier plate at the lower end of a rudder of an underwater vehicle, characterized in that: include: S100, determining the installation position of the rectifier plate according to the installation position of the rudder of the underwater vehicle, and preliminarily determining the top view shape and size of the rectifier plate; S200, establishing a three-dimensional model of the underwater vehicle and the rudder, using a computational fluid dynamics method to determine the flow field and streamline shape near the installation position of the rectifier, and determining the side shape of the rectifier based on the flow field and streamline shape; S300, with the goal of suppressing the flow around the rudder end, considering the effect of the fairing on the rudder lift and drag, using computational fluid dynamics methods to optimize the installation position, top view shape, size, and side profile of the fairing, determine a preliminary design scheme for the fairing, and optimize the fairing parameters with reference to the flow field uniformity of the propeller disk of the underwater vehicle; S400, considering the interference of the suction effect of the underwater vehicle propeller on the flow field around the rectifier, establishing a numerical calculation model of the underwater vehicle, rudder, rectifier, and propeller, evaluating the influence of the propeller on the rectifier, and adjusting the rectifier parameters; Step S400 includes: S401. On the basis of step S300, according to the specific parameters and layout of the propellers, corresponding propellers are added to the model to establish a numerical calculation model of the underwater vehicle, rudder, fairing, and propellers; S402. Solve the numerical calculation model using a CFD solver to obtain detailed flow information of the flow field around the rectifier, analyze the specific effects of the propeller suction on the flow field around the rectifier, and evaluate the potential impact of these effects on the performance of the rectifier; S403. Based on the numerical simulation results, identify key parameters that significantly affect the performance of the rectifier plate, make preliminary adjustments to the key parameters, re-run the numerical simulation to evaluate the adjustment effects, and perform numerical simulation verification on the optimized rectifier plate to ensure that it meets the design requirements while minimizing the impact of the thruster's suction effect. S500: Perform hydrodynamic analysis on the numerical calculation models of the underwater vehicle, rudder, and propeller, and determine the final design of the rectifier in combination with maneuverability, speed, and stealth indicators.

2. The design method for fixing a rectifier plate at the lower end of a rudder of an underwater vehicle according to claim 1, characterized in that: Step S100 includes: S101. Determine the relative position of the straightening plate on the vehicle based on the installation position of the rudder and the clearance between the straightening plate and other components of the vehicle, and fine-tune the installation position and angle of the straightening plate based on flow field characteristics. S102. Determine the top view shape of the rectifier plate according to the design requirements, and preliminarily estimate the size of the rectifier plate according to relevant specifications or empirical formulas, and adjust and optimize it in the subsequent process.

3. The design method for fixing a rectifier plate at the lower end of a rudder of an underwater vehicle according to claim 1, characterized in that: Step S200 includes: S201, using three-dimensional modeling software to establish a model of the underwater vehicle and rudder, and performing grid division on the model; S202. Import the data into professional CFD software, set boundary conditions according to actual working conditions, run CFD simulation, monitor the convergence and stability of the simulation process, and analyze the flow field and streamline shape at the rectifier installation location; S203 : Determine the side shape of the rectifier plate according to the flow field and streamline shape at the installation position of the rectifier plate.

4. The design method for fixing a rectifier plate at the lower end of a rudder of an underwater vehicle according to claim 3, characterized in that: Step S201 includes: appropriately simplifying the underwater vehicle and rudder models according to the needs of CFD simulation, and removing details that have little impact on fluid flow.

5. A method for designing a fixed fairing plate at the lower end of a rudder of an underwater vehicle according to any one of claims 1 to 4, characterized in that: Step S300 includes: S301. Based on experience and preliminary simulation results, preliminary solutions for rectifiers with various geometric parameters are designed. The effects of the rectifiers on the lift and drag of the rudder are evaluated according to steps S201 and S202. After each calculation converges, the rectifier parameters are continuously adjusted according to the simulation results to seek the optimal solution. S302. Adjust the parameters of the mother rectifier plate to view the influence of different parameters on the flow field uniformity of the propeller disc, compare the flow field uniformity of the propeller disc surface after the mother rectifier plate is optimized with the flow field uniformity of the original propeller disc surface, and evaluate the improvement effect.

6. A fixed rectifier plate for the lower end of a rudder of an underwater vehicle, which is realized by applying the design method for fixed rectifier plates for the lower end of a rudder of an underwater vehicle as described in claims 1 to 5, characterized in that: It can effectively suppress the flow around the lower end face of the rudder of the underwater vehicle, reduce the lateral flow of the rudder, and prevent the fluid from flipping over and forming a separation vortex at the rudder end when the rudder angle is small; the straightening plate is arranged at the gap between the rear end of the stabilizing wing and the rotating rudder, and is installed on the upper end face of the stabilizing wing. The plane is perpendicular to the rudder surface, and the side shape is the same as the streamline shape at the installation position.

7. The fixing straightening plate for the lower end of the rudder of an underwater vehicle according to claim 6, characterized in that: The top view shape of the straightening plate can be changed accordingly according to the flow field near the rudder.

8. The fixing straightening plate for the lower end of the rudder of an underwater vehicle according to claim 6, characterized in that: The top view shape of the fairing can adopt a specific airfoil profile or be the same as the rudder wing section to maximize the benefit of the fairing.

9. A design system for fixing a fairing at the lower end of an underwater vehicle rudder, characterized in that: include: The first module determines the installation position of the fairing according to the rudder installation position of the underwater vehicle, and preliminarily determines the top view shape and size of the fairing; The second module establishes a three-dimensional model of the underwater vehicle and the rudder, uses computational fluid dynamics to determine the flow field and streamline shape near the installation location of the fairing, and determines the side shape of the fairing based on the flow field and streamline shape; The third module aims to suppress the flow around the rudder end, taking into account the effect of the fairing on the rudder lift and drag. Computational fluid dynamics methods are used to optimize the installation position, top view shape, size, and side profile of the fairing. The preliminary design scheme of the fairing is determined, and the fairing parameters are optimized based on the uniformity of the propeller disk flow field of the underwater vehicle. The fourth module considers the interference of the suction effect of the underwater vehicle propeller on the flow field around the rectifier, establishes a numerical calculation model of the underwater vehicle, rudder, rectifier, and propeller, evaluates the impact of the propeller on the rectifier, and adjusts the rectifier parameters; The fourth module specifically performs the following steps: On the basis of the adjustment of the third module, according to the specific parameters and layout of the propeller, the corresponding propeller is added to the model to establish the numerical calculation model of the underwater vehicle, rudder, fairing and propeller; Using a CFD solver to solve the numerical calculation model, detailed flow information of the flow field around the rectifier is obtained, the specific effects of the propeller suction on the flow field around the rectifier are analyzed, and the potential impact of these effects on the performance of the rectifier is evaluated; Based on the numerical simulation results, key parameters that have a significant impact on the performance of the rectifier are identified, and preliminary adjustments are made to these key parameters. Numerical simulations are then repeated to evaluate the effects of these adjustments. The optimized rectifier is then numerically verified to ensure that it meets the design requirements while minimizing the impact of the thruster's suction. The fifth module conducts hydrodynamic analysis on the numerical calculation models of the underwater vehicle, rudder and propeller, and determines the final design scheme of the fairing based on the maneuverability, speed and stealth indicators.

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