A method and device for predicting the attitude of a stream-induced vibration mode of a towed array
By combining quasi-static and dynamic models, and considering the boundary constraints and actual forces of the towed linear array, the problem of accuracy in predicting the flow-induced vibration configuration of the towed linear array was solved, and accurate prediction and rapid engineering application of the flow-induced vibration configuration and attitude of the towed linear array were realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 汉江国家实验室
- Filing Date
- 2026-03-19
- Publication Date
- 2026-07-10
AI Technical Summary
Existing technologies cannot accurately predict the flow-induced vibration configuration and attitude of towed linear arrays under different towing conditions, especially since they fail to simultaneously consider the effects of fluid dynamic coefficients, structural tension, and gravity.
A combination of quasi-static and dynamic models is adopted. By solving a set of nonlinear equations considering boundary constraints, the configuration and tension of the towed linear array at the equilibrium position are determined. Using this as the initial condition, the dynamic model is discretized. Combined with the segment tension and gravity, a set of dynamic equations including tangential fluid forces is formed. The set of ordinary differential equations is iteratively solved to obtain the spatiotemporal distribution characteristics of the flow-induced vibration displacement.
It achieves accurate prediction of the vibration configuration and attitude of the towed array current, which conforms to its actual stress conditions, overcomes the limitations of existing technologies, and can be quickly applied in engineering.
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Figure CN122365984A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of marine exploration technology, specifically to a method and device for predicting the configuration and attitude of a towed array current-induced vibration. Background Technology
[0002] Towed linear arrays (TLA) are widely used in marine geological exploration and underwater target detection. They are slender, flexible structures composed of hydrophone arrays. During towing, the resulting flow-induced vibrations distort the array's shape, interfering with target localization. Establishing a dynamic model of the flow-induced vibrations of TLAs based on gridded numerical methods to predict the flow-induced vibration configuration and attitude of TLAs with different structural dimensions under various towing conditions is currently a popular research direction in array shape estimation.
[0003] Milinazzo et al. published "An Efficient Algorithm for Simulating the Dynamics of Towed Cable Systems" in Ocean Engineering, which describes the use of a finite difference model to predict the quasi-static configuration and attitude changes of towed cable arrays of different structural dimensions under different towing velocities and directions. However, their assumption that the hydrodynamic coefficients are constant makes it impossible to calculate the dynamic configuration of flow-induced vibrations. Qu et al. published "Modelling of Coupled Cross-flow and In-line Vortex-induced Vibrations of Flexible Cylindrical Structures. Part 1: Model Description and Validation" in Nonlinear Dynamics, which describes the use of the finite element method and wake oscillator model to predict the dynamic configuration of flow-induced vibrations of marine risers. However, because it does not consider the effects of structural tension and gravity, it cannot be directly applied to the prediction of flow-induced vibration configurations of towed cable arrays. Summary of the Invention
[0004] This application provides a method and apparatus for predicting the configuration and attitude of a towed linear array under flow-induced vibration, taking into account the actual stress conditions of the towed linear array, thereby achieving accurate prediction of the configuration and attitude of the towed linear array under flow-induced vibration.
[0005] In a first aspect, embodiments of this application provide a method for predicting the configuration and attitude of a towed linear array under flow excitation, the method comprising: A quasi-static model is used to determine the configuration and tension of the towed array at the equilibrium position by solving a set of nonlinear equations that take into account boundary constraints; wherein, the tail boundary conditions of the quasi-static model include the tail rope tension. A dynamic model is adopted, with the configuration and tension as initial conditions. The dynamic model is discretized and solved to obtain the spatiotemporal distribution characteristics of the displacement of the towed array flow-induced vibration. The dynamic model includes segment tension and gravity.
[0006] In conjunction with the first aspect, in one implementation, the use of a quasi-static model to determine the configuration and tension of the towed array at the equilibrium position by solving a system of nonlinear equations considering boundary constraints includes: Establish the continuous dynamic equations of the towed linear array; The towed array system is discretized into multiple units, and the head and tail boundary conditions are set, wherein the tail boundary condition includes the tail rope tension. Solve the discretized nonlinear equations to obtain the configuration and tension at the equilibrium position.
[0007] In conjunction with the first aspect, in one implementation, the towed array system is discretized into multiple units using the finite difference method; and the discretized nonlinear equations are solved using an iterative numerical method.
[0008] In conjunction with the first aspect, in one implementation, the dynamic model uses a wake oscillator model to describe the dynamic excitation force, and the discretization of the dynamic model includes: The dynamic equations containing segment tension and gravity are discretized into multiple element equations. The element stiffness matrices contained in each element equation are corrected by combining the segment tension and then assembled to obtain the set of ordinary differential equations for the overall flow-induced vibration excitation and response.
[0009] In conjunction with the first aspect, in one embodiment, the discretization of the dynamic equations containing segment tension and gravity into multiple element equations includes: Based on the kinematic equations of response of the towed array structure, the segment tension is added to the virtual work done by the internal forces, and gravity is added to the virtual work done by the external forces, forming a dynamic equation that includes segment tension and gravity. The dynamic model is discretized into multiple elements using the finite element method, and the dynamic equations within each element are the element equations.
[0010] In conjunction with the first aspect, in one embodiment, the dynamic equations that include segment tension and gravity further include tangential fluid force, adding tangential fluid force to the virtual work done by external forces to form dynamic equations that include segment tension, gravity and tangential fluid force.
[0011] In conjunction with the first aspect, in one implementation, the system of ordinary differential equations is performed and solved to obtain the spatiotemporal distribution characteristics of the displacement induced by the towed linear array flow, including: Establish the head boundary conditions, considering the constraints of the towing point, establish the tail boundary conditions, and add the tail rope tension; iteratively solve the set of ordinary differential equations to obtain the spatiotemporal distribution characteristics of the displacement of the towed linear array flow-induced vibration.
[0012] In conjunction with the first aspect, in one embodiment, the set of ordinary differential equations for the overall flow-induced vibration excitation and response is as follows: ; ; in, This represents the displacement of the drag-and-drop linear array system after the matrix is assembled. It represents the first derivative of displacement with respect to time (velocity). It represents the second derivative of displacement with respect to time (acceleration). This represents the mass matrix corresponding to the displacement. This represents the damping matrix corresponding to the displacement. This represents the stiffness matrix corresponding to the displacement. This represents the mass matrix corresponding to the wake variable, and F represents the external force. Represents the wake variable. This represents the first derivative of the wake variable with respect to time. This represents the second derivative of the wake variable with respect to time. This represents the damping matrix corresponding to the wake variable. This represents the stiffness matrix corresponding to the wake variable. The load represents the wake variable.
[0013] Secondly, embodiments of this application provide a device for predicting the configuration and attitude of a towed linear array current-induced vibration, the device comprising: The quasi-static model module is used to determine the configuration and tension of the towed array at the equilibrium position by solving a system of nonlinear equations considering boundary constraints; wherein, the tail boundary conditions of the quasi-static model include the tail rope tension. The dynamic model module is used to discretize and solve the dynamic model using the configuration and tension as initial conditions to obtain the spatiotemporal distribution characteristics of the displacement of the towed array flow-induced vibration; wherein, the dynamic model includes segment tension and gravity.
[0014] In conjunction with the second aspect, in one implementation, the dynamic model uses a wake oscillator model to describe the dynamic excitation force, and the dynamic model is used for: Based on the kinematic equations of the towed linear array structure response, segment tension is added to the virtual work done by internal forces, and gravity and tangential fluid force are added to the virtual work done by external forces to form dynamic equations. The dynamic equations are discretized into multiple element equations, and the element stiffness matrix contained in each element equation is corrected by combining the segment tension and assembled to obtain the set of ordinary differential equations for the overall flow-induced vibration excitation and response. The set of ordinary differential equations is solved iteratively to obtain the spatiotemporal distribution characteristics of the flow-induced vibration displacement of the towed linear array.
[0015] The beneficial effects of the technical solutions provided in this application include: A quasi-static model is employed, which determines the configuration and tension of the towed wire array at its equilibrium position by solving a system of nonlinear equations considering boundary constraints. The tail boundary conditions of the quasi-static model include tail rope tension. A dynamic model is used, with the configuration and tension as initial conditions. The dynamic model is discretized and solved to obtain the spatiotemporal distribution characteristics of the towed wire array's flow-induced vibration displacement. The dynamic model includes segment tension and gravity. By combining the quasi-static and dynamic models and adding tail rope tension, segment tension, and gravity to the existing parameters, the model conforms to the actual stress conditions of the towed wire array, thereby achieving accurate prediction of the spatiotemporal distribution of the towed wire array's flow-induced vibration configuration. Attached Figure Description
[0016] Figure 1 This is a flowchart illustrating an embodiment of the method for predicting the configuration and attitude of a towed linear array current-induced vibration in this application. Figure 2 This is a flowchart illustrating the process of determining the configuration and tension of the towed array at the equilibrium position using a quasi-static model in this embodiment of the application. Figure 3 This is a flowchart illustrating the process of obtaining the spatiotemporal distribution characteristics of the displacement of the towed linear array flow-induced vibration using a dynamic model in this embodiment of the application. Figure 4 This is a schematic diagram of the configuration and attitude of the towed linear array under three different times in the embodiments of this application. Detailed Implementation
[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.
[0018] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0019] Firstly, this application provides an embodiment of a method for predicting the configuration and attitude of a towed linear array subjected to flow-induced vibration. For example... Figure 1 As shown, the method for predicting the configuration and attitude of a towed linear array under flow excitation includes the following steps: S1: Using a quasi-static model, the configuration and tension of the towed array at the equilibrium position are determined by solving a set of nonlinear equations considering boundary constraints; the tail boundary conditions of the quasi-static model include the tail rope tension.
[0020] S2: Using a dynamic model, the dynamic model is discretized and solved with the configuration and tension of the towed array at the equilibrium position as the initial conditions. The spatiotemporal distribution characteristics of the flow-induced vibration displacement of the towed array are obtained, and the configuration and attitude of the towed array are predicted. The dynamic model includes the segment tension and gravity.
[0021] In this embodiment, by combining quasi-static and dynamic models, tail rope tension, array segment tension, and gravity are added, which solves the problem in related technologies that the wake oscillator model cannot be directly applied to the prediction of flow-induced vibration configuration of towed arrays. This embodiment overcomes the limitation of existing technologies that cannot simultaneously consider quasi-static equilibrium and dynamic vibration, conforms to the actual stress conditions of towed arrays, and thus achieves accurate prediction of the spatiotemporal distribution of flow-induced vibration configuration of towed arrays.
[0022] like Figure 2 As shown, step S1 above specifically includes the following steps: S11: Establish the continuous dynamic equations of the towed linear array.
[0023] S12: Discretize the towed linear array system into multiple elements, and set the head and tail boundary conditions, wherein the tail boundary condition includes the tail rope tension.
[0024] S13: Solve the discretized nonlinear equations to obtain the configuration and tension at the equilibrium position.
[0025] The quasi-static model is based on the existing dynamic model of the towed array system, which includes the towed cable section, the vibration isolation section, and the acoustic array section. It is achieved by changing the boundary conditions at the tail of the towed array and adding the tail rope tension to the model.
[0026] Specifically, in S11 above, the quasi-static model uses the following continuous dynamic equations for the drag-and-drop array: (Equation 1) The vector to be solved is: ; Where s is the arc length coordinate before structural deformation, also known as the Lagrange coordinate; t is time; and T is the tension at each location. It is the velocity in the local coordinate system. The subscripts t, n, and b represent the tangential, normal, and transverse directions, respectively. These are heading and pitch angle, respectively.
[0027] ; ; ; in, , and They are all matrices that combine multiple physical quantities. It is the density of water. It is the mass per unit length of the array segment. It is the cross-sectional area of the array segment. It is the virtual mass per unit length of the array segment. ; It is gravitational acceleration. It is the wet weight per unit length of the array segment. ; It is the tensile modulus of elasticity of the segment. , and These are the tangential fluid drag coefficient and the normal fluid drag coefficient, respectively. It is the array segment diameter. This refers to the ocean current velocity in a local coordinate system, where the subscripts t, n, and b represent the tangential, normal, and transverse directions, respectively. yes The derivative with respect to time, It is the speed of the towline array relative to the ocean current. .
[0028] Furthermore, in S12 above, the finite difference method is used to discretize the towed linear array system into multiple elements, resulting in Equation 2:
[0029] (Equation 2) in, , j It is the spatial node number. i It is a time sequence number, for example Indicates the first j The node at the th i The coordinates at a given moment. and These are the spatial and temporal steps, respectively.
[0030] Establish the head and tail boundary conditions. The boundary conditions for the dragging linear array consist of two sets of equations: the head and the tail. The tail boundary conditions are as follows: (Equation 4) (Equation 5) (Equation 6) in It's the tension of the tail rope. It refers to the number of elements. Equation 4 incorporates the actual tension of the tail rope into the model, while Equations 5 and 6 show that the last element of the towed array does not bend relative to the previous element, which can be considered a reasonable assumption.
[0031] The boundary conditions for the head of the towed array are as follows: Equation 7: (Equation 7) in It's the speed of the tugboat. .
[0032] Furthermore, in S13 above, an iterative numerical method is used to solve the discretized nonlinear equation system. Specifically, the Newton-Raphson method is used to iteratively solve Equation 8 (the total linear equation system for all elements): (Equation 8) in, ; As shown in Equation 2 above. (Equation 9) (Equation 10) Finally, the configuration and orientation of the towed array at its equilibrium position are obtained. and tension superscript eq This represents the coordinates at the equilibrium position.
[0033] like Figure 3 As shown, step S2 above specifically includes the following steps: S21: The dynamic model uses a wake oscillator model to describe the dynamic excitation force, and the dynamic model is discretized. Specifically, the dynamic equations containing segment tension and gravity are discretized into multiple element equations. The element stiffness matrices contained in each element equation are corrected by combining the segment tension and then assembled to obtain the set of ordinary differential equations for the overall flow-induced vibration excitation and response.
[0034] S22: Establish head boundary conditions, consider the constraints of the drag point, establish tail boundary conditions, and add tail rope tension.
[0035] S23: Iteratively solve the above set of ordinary differential equations to obtain the spatiotemporal distribution characteristics of the displacement of the towed linear array flow-induced vibration.
[0036] The following is a detailed description of each of the above steps. The configuration and tension of the towed array at its equilibrium position are used as inputs to the dynamic model. The dynamic model calculates the response of the towed array system under dynamic excitation force, with the quasi-static attitude as the equilibrium position.
[0037] In S21 above, the dynamic equations containing segment tension and gravity are discretized into multiple element equations. Specifically, based on the kinematic equations of the response of the towed array structure, segment tension is added to the virtual work done by internal forces, and gravity is added to the virtual work done by external forces to form dynamic equations containing segment tension and gravity. The dynamic model is discretized into multiple elements using the finite element method, and the dynamic equations in each element are element equations.
[0038] Specifically, the dynamic configuration attitude vector of the towed linear array for: (Equation 11) Where s is the Lagrange coordinate and t is time, the kinematic equations for the weak form of the dragline array structure response are: (Equation 12) in, It is the work done by inertia. It's a feint done by internal energy. It is a work done by external forces that is essentially ineffective.
[0039] (Equation 13) (Equation 14) in, It is the unit length. It is the mass per unit length of the array segment. It is the moment of inertia. It is axial strain. It is the radius of curvature of the material. r It is the configuration attitude, and the two points above it represent the second derivative (acceleration) with respect to the event.
[0040] In this embodiment, the virtual work that needs to be done by internal force is required. Adding segment tension to the middle, the virtual work done by external force Gravity is incorporated to form dynamic equations that include segment tension and gravity, in order to conform to the actual stress conditions of the towed array and ensure computational convergence.
[0041] Specifically, in existing technologies, computation At that time, only the elastic force generated by axial tensile strain and bending strain was considered (as in Equation 14). For a towed array, since there is tension along the length direction inside the array segment, the virtual work done by the tension is considered, and Equation 14 is modified to Equation 14′: (Equation 14') in, It refers to the tension at each location.
[0042] For towed cable array systems, if there is zero buoyancy in the water, gravity can be ignored. However, in order to allow the towed cable array to sink to a specified depth, the tow cable is usually designed with negative buoyancy. In addition, the vibration isolation section and the acoustic array section are not strictly zero buoyancy. Therefore, the net weight of the array section cannot be ignored, and the external forces (gravity and buoyancy) can be expressed as: (Equation 15) in It is the density of water. It is a unit vector in the vertical direction.
[0043] Furthermore, in one embodiment, the kinetic equations also include tangential fluid forces, the effect of which has not been considered in existing technologies. Tangential fluid forces It can be represented as: (Equation 16) in, It is the fluid density (in this embodiment, the fluid is water). It is the array segment diameter. It is the tangential hydrodynamic coefficient. It is the tangential relative velocity. S is the interpolation function of the array element. It is the tangential unit vector of the configuration in the quasi-static model. It refers to the incoming flow velocity.
[0044] (Equation 17) in, , , , , (Equation 18) Among them, subscript Let represent the partial derivative with respect to s. It is the configuration and orientation of the quasi-static model.
[0045] In this embodiment, adding tangential fluid force can further increase the accuracy of predicting the spatiotemporal distribution of the dynamic configuration of the towed linear array.
[0046] In S21 above, the dynamic model is discretized into multiple elements using the finite element method. The dynamic equations within each element are element equations. The element stiffness matrices contained in each element equation are corrected by combining the segment tension and then assembled to obtain the set of ordinary differential equations for the overall flow-induced vibration excitation and response. This process is described in detail below using formulas.
[0047] Substitute equations 14', 15, and 16 into equation 12 (in equation 12) (keeping unchanged), Equation 12 is discretized into multiple elements using the finite element method, and then combined to obtain the existing set of ordinary differential equations (Equations 19 and 20): (Equation 19) (Equation 20) (Equation 21) It is a new external force term, which, based on the external forces in existing technology, adds gravity and tangential fluid force. It is a variable in the wake oscillator model. q The function, where the superscript Indicates the unit number. , It is the number of finite element elements. u This refers to the displacement of each element. The forces acting on the wake oscillator. It is the transient acceleration of the towed array. The function is given by equations 19 and 20, which characterize the fluid-structure interaction properties of the towed linear array system.
[0048] In this embodiment, since segment tension is taken into account, an additional term is added within the integral sign. Stiffness matrix of each finite element as follows: (Equation 22) in The definition is as follows: (Equation 23) The expression is: (Equation 24) (Equation 25) in It is an empirical constant. .
[0049] The expressions are as follows: (Equation 26) in ; (Equation 27) in It is the Strouhal frequency. ; It is a Strouhal number. ; These are the coordinates of the wake element, and the subscript is... and These represent the two nodes before and after each unit.
[0050] (Equation 28) in =5 is a constant parameter. It is a unit vector flowing towards the destination. ; It is the projection of the incoming flow velocity onto the normal direction. .
[0051] By combining the element stiffness matrices in each element equation with the segment tension correction and assembling them, the following set of ordinary differential equations for the overall flow-induced vibration excitation and response is obtained: (Equation 19') (Equation 20') in, This represents the displacement of the drag-and-drop linear array system after the matrix is assembled. It represents the first derivative of displacement with respect to time (velocity). It represents the second derivative of displacement with respect to time (acceleration). This represents the mass matrix corresponding to the displacement. This represents the damping matrix corresponding to the displacement. This represents the stiffness matrix corresponding to the displacement. This represents the mass matrix corresponding to the wake variable, and F represents the external force. Represents the wake variable. This represents the first derivative of the wake variable with respect to time. This represents the second derivative of the wake variable with respect to time. This represents the damping matrix corresponding to the wake variable. This represents the stiffness matrix corresponding to the wake variable. The load represents the wake variable.
[0052] (Equation 29) (Formula 30) The subscripts A and B represent the two nodes before and after each element. For ease of representation, the 12×12 mass matrix is divided into four 6×6 submatrices, i.e. .
[0053] Furthermore, in S22 above, the head boundary conditions are established, taking into account the constraints of the towing point, and the tail boundary conditions are established, adding the tail rope tension, specifically including: The bow boundary conditions, with the mother ship as the reference frame, are such that, since the bow displacement of the towed array is zero, the above equation 29 is applied according to the method of setting large numbers. Set the diagonal elements to large numbers (e.g., ), and at the same time, in equation 30 Set all elements to 0.
[0054] Tail boundary conditions, in Equation 30, do not consider the boundary conditions, namely the tail rope tension, towards Add tail rope tension : (Equation 31) According to the definition in Equation 18 above, It is the tangential unit vector at the tail of the equilibrium position of the drag array, calculated by the quasi-static model.
[0055] Combining the steps of the above-mentioned head boundary conditions and tail boundary conditions, Equation 29 above should be rewritten after considering the boundary conditions as follows: (Equation 29') Where I is a 6×6 identity matrix, and Equation 30 above should be rewritten as: (Formula 30') Furthermore, in S23 above, the Newton-Raphson method is used to iteratively solve the above set of ordinary differential equations (Equations 19′ and 20′) to obtain the spatiotemporal distribution of the displacement of the towed linear array current-induced vibration. This completes the entire calculation process for predicting the configuration and attitude of flow-induced vibration.
[0056] If similar research were conducted on commercial CFD software, direct calculation of the flow field would be required, resulting in a massive computational domain and a large number of meshes, demanding high computational resources and suffering from long computation times and difficulty in achieving convergence. In the above embodiments, the wake oscillator model (represented by q in the text above) is used in the dynamic model, saving fluid computational resources. Calculations are performed only on the towed array structure, thus efficiently characterizing the fluid-structure interaction properties of the system (see Equations 19′ and 20′), enabling rapid engineering-level prediction. Therefore, this application employs a combination of quasi-static and dynamic models, ensuring that the calculation results not only conform to the actual stress conditions of the towed array but also achieve rapid engineering-level prediction, filling a technological gap in the field of flow-induced vibration configuration prediction for towed arrays.
[0057] Since the complete calculation result is a 3D animation of the configuration and attitude of the towed wire array over time, screenshots are used here for illustration. Based on the calculation results, screenshots of the flow-excited configuration and attitude of the towed wire array at three different time points are shown below. Figure 4As shown, these screenshots depict the process of vibration propagating backward from the head of the towed array, being reflected at the tail, and then propagating forward again, thus forming traveling waves and standing waves. For example, 4a1 and 4b1, 4a2 and 4b2, and 4a3 and 4b3 represent the process of vibration propagating backward from the head of the towed array, being reflected at the tail, and then propagating forward again at different times, thus forming the superposition of traveling waves and standing waves. For example, 4a1 and 4b1 are the side view and top view of the towed array configuration at the first time, respectively; 4a2 and 4b2 are the side view and top view of the towed array configuration at the second time, respectively; and 4a3 and 4b3 are the side view and top view of the towed array configuration at the third time, respectively.
[0058] Secondly, this application provides an embodiment of a towed linear array flow-induced vibration configuration and attitude prediction device, the core device including a quasi-static model module and a dynamic model module.
[0059] The quasi-static model module is used to determine the configuration and tension of the towed array at the equilibrium position by solving a set of nonlinear equations that take into account boundary constraints; the tail boundary conditions of the quasi-static model include the tail rope tension.
[0060] The dynamic model module is used to discretize and solve the dynamic model using the configuration and tension as initial conditions to obtain the spatiotemporal distribution characteristics of the displacement of the towed array flow-induced vibration; wherein, the dynamic model includes segment tension and gravity.
[0061] Furthermore, the dynamic model uses a wake oscillator model to describe the dynamic excitation force. The dynamic model is used for: Based on the kinematic equations of the towed linear array structure response, segment tension is added to the virtual work done by internal forces, and gravity and tangential fluid force are added to the virtual work done by external forces to form dynamic equations. The dynamic equations are discretized into multiple element equations, and the element stiffness matrix contained in each element equation is corrected by combining the segment tension and assembled to obtain the set of ordinary differential equations for the overall flow-induced vibration excitation and response. The set of ordinary differential equations is solved iteratively to obtain the spatiotemporal distribution characteristics of the flow-induced vibration displacement of the towed linear array.
[0062] The functions of each module in the above-mentioned towed array flow-induced vibration configuration and attitude prediction device correspond to the steps in the above-mentioned towed array flow-induced vibration configuration and attitude prediction method embodiment, and their functions and implementation processes will not be described in detail here.
[0063] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0064] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.
[0065] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.
[0066] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.
[0067] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.
[0068] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.
[0069] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.
Claims
1. A method for predicting the configuration and attitude of a towed linear array current-induced vibration, characterized in that, The method includes: A quasi-static model is used to determine the configuration and tension of the towed array at the equilibrium position by solving a set of nonlinear equations that take into account boundary constraints; wherein, the tail boundary conditions of the quasi-static model include the tail rope tension. A dynamic model is adopted, with the configuration and tension as initial conditions. The dynamic model is discretized and solved to obtain the spatiotemporal distribution characteristics of the displacement of the towed array flow-induced vibration. The dynamic model includes segment tension and gravity.
2. The method for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 1, characterized in that, The aforementioned quasi-static model, by solving a system of nonlinear equations considering boundary constraints, determines the configuration and tension of the towed linear array at the equilibrium position, including: Establish the continuous dynamic equations of the towed linear array; The towed array system is discretized into multiple units, and the head and tail boundary conditions are set, wherein the tail boundary condition includes the tail rope tension. Solve the discretized nonlinear equations to obtain the configuration and tension at the equilibrium position.
3. The method for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 2, characterized in that: The towed array system is discretized into multiple units using the finite difference method; the discretized nonlinear equations are solved using an iterative numerical method.
4. The method for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 1, characterized in that, The dynamic model uses a wake oscillator model to describe the dynamic excitation force. The discretization of the dynamic model includes: The dynamic equations containing segment tension and gravity are discretized into multiple element equations. The element stiffness matrices contained in each element equation are corrected by combining the segment tension and then assembled to obtain the set of ordinary differential equations for the overall flow-induced vibration excitation and response.
5. The method for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 4, characterized in that, The discretization of the dynamic equations, which include segment tension and gravity, into multiple element equations includes: Based on the kinematic equations of response of the towed array structure, the segment tension is added to the virtual work done by the internal forces, and gravity is added to the virtual work done by the external forces, forming a dynamic equation that includes segment tension and gravity. The dynamic model is discretized into multiple elements using the finite element method, and the dynamic equations within each element are the element equations.
6. The method for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 5, characterized in that, The dynamic equations that include segment tension and gravity also include tangential fluid force. Tangential fluid force is added to the virtual work done by external forces to form dynamic equations that include segment tension, gravity and tangential fluid force.
7. The method for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 4, characterized in that, The spatiotemporal distribution characteristics of the displacement induced by the towed linear array flow are obtained by performing and solving the aforementioned set of ordinary differential equations, including: Establish the head boundary conditions, considering the constraints of the towing point, establish the tail boundary conditions, and add the tail rope tension; iteratively solve the set of ordinary differential equations to obtain the spatiotemporal distribution characteristics of the displacement of the towed linear array flow-induced vibration.
8. The method for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 4, characterized in that, The set of ordinary differential equations for the overall flow-induced vibration excitation and response is as follows: ； ； in, This represents the displacement of the drag-and-drop linear array system after the matrix is assembled. It represents the first derivative of displacement with respect to time (velocity). It represents the second derivative of displacement with respect to time (acceleration). This represents the mass matrix corresponding to the displacement. This represents the damping matrix corresponding to the displacement. This represents the stiffness matrix corresponding to the displacement. This represents the mass matrix corresponding to the wake variable, and F represents the external force. Represents the wake variable. This represents the first derivative of the wake variable with respect to time. This represents the second derivative of the wake variable with respect to time. This represents the damping matrix corresponding to the wake variable. This represents the stiffness matrix corresponding to the wake variable. The load represents the wake variable.
9. A device for predicting the configuration and attitude of a towed linear array current-induced vibration, characterized in that, The device includes: The quasi-static model module is used to determine the configuration and tension of the towed array at the equilibrium position by solving a system of nonlinear equations considering boundary constraints; wherein, the tail boundary conditions of the quasi-static model include the tail rope tension. The dynamic model module is used to discretize and solve the dynamic model using the configuration and tension as initial conditions to obtain the spatiotemporal distribution characteristics of the displacement of the towed array flow-induced vibration; wherein, the dynamic model includes segment tension and gravity.
10. The device for predicting the configuration and attitude of a towed linear array current-induced vibration as described in claim 9, characterized in that, The dynamic model uses a wake oscillator model to describe the dynamic excitation force. The dynamic model is used for: Based on the kinematic equations of response of the towed linear array structure, the segment tension is added to the virtual work done by the internal forces, and gravity and tangential fluid force are added to the virtual work done by the external forces to form the dynamic equations. The dynamic equations are discretized into multiple element equations. The element stiffness matrices contained in each element equation are corrected by combining the segment tension and assembled to obtain the set of ordinary differential equations for the overall flow-induced vibration excitation and response. The set of ordinary differential equations is solved iteratively to obtain the spatiotemporal distribution characteristics of the flow-induced vibration displacement of the towed linear array.