Method, device, medium and equipment for calculating water dynamics of coupling of moon pool and platform

Abstract

The application relates to a kind of moon pool and platform coupling hydrodynamic calculation method, device, medium and equipment, method includes: establishing platform model not containing moon pool;Solve the spatial velocity potential of flow field in platform model;In the platform model, the physical attribute parameters of mooring and riser system are input, the platform mooring system model is established, and initialization is completed;Solve the wave force of each order, mooring tension and riser force suffered by platform model under initial time step;Solve the platform coupling motion equation of platform model not containing fluid force in moon pool, obtain the six-degree-of-freedom motion displacement of platform model;Complete initialization flow field;The six-degree-of-freedom motion of platform model six-degree-of-freedom motion displacement is specified as the six-degree-of-freedom motion of overlapping grid area;Solve the nonlinear motion of water body in moon pool, obtain the parameters including fluid pressure to obtain the fluid force in moon pool;Solve the time-domain motion equation of moon pool and platform coupling, repeatedly iterate, until the last step time calculation is completed.

Description

TECHNICAL FIELD

[0001] The application relates to a method, device, medium and equipment for calculating water dynamics of a moon pool and a platform coupling, and belongs to the technical field of water dynamics calculation of marine structures. BACKGROUND

[0002] To meet the needs of offshore operations such as oil and gas resource development, marine mineral resources and marine scientific investigation, moon pools are widely used in offshore engineering structures such as oil and gas exploration platforms, drilling ships and deep-sea Spar platforms. The main function of the moon pool is to provide a lowering and operating channel for underwater important equipment such as a drilling platform and a drilling riser, a tensioned production riser (TTR), a blowout preventer (BOP) and a Christmas tree.

[0003] The internal water body of the moon pool is in communication with the external seawater, and the internal water body movement is affected by external excitation. Under some special resonance conditions, the internal water body may move violently, and the vertical climbing height may even reach three to four times the height of the external environment wave. Such strong resonance of the internal water body of the moon pool not only causes slamming on the equipment and ship structure in the moon pool, but also causes extreme phenomena such as green water on the moon pool edge working deck, which seriously threatens the safety of personnel and equipment. The water dynamic coupling effect between the moon pool and the platform may exacerbate the heave and roll motion of the platform, resulting in a sharp decline in the motion performance of the platform.

[0004] At present, in the preliminary stage of water dynamic design, the traditional linear potential flow theory is used to obtain the overall water dynamic performance of the moon pool and the platform. However, under resonance conditions, i.e. when the internal water body of the moon pool moves violently, the linear potential flow theory cannot consider the nonlinear characteristics of the fluid response in the moon pool, and the prediction results may deviate greatly, and the coupled water dynamic characteristics of the moon pool and the platform are unknown.

[0005] How to accurately predict the nonlinear water dynamic response of the coupling between the internal water body of the moon pool and the platform, and improve the motion performance of the floating platform, suppress the resonance of the moon pool water body and adapt to the needs of dry tree production, is the focus and difficulty in the field of offshore engineering. SUMMARY

[0006] In view of the above technical problems, the application provides a method, device, medium and equipment for calculating water dynamics of a moon pool and a platform coupling, which combines viscous computational fluid dynamics and potential flow theory method, considers the complex motion characteristics of the fluid response in the moon pool, realizes the coupling calculation of the moon pool and the platform motion, and can effectively solve the nonlinear water dynamic problem of the coupling between the internal water body of the moon pool and the platform system.

[0007] To achieve the above purpose, the application adopts the following technical scheme:

[0008] A method for calculating water dynamics of a moon pool and a platform coupling, comprising:

[0009] S1: based on three-dimensional potential flow theory, a platform model not containing moon pool is established, environmental parameters are set, surface boundary grid of the platform model is divided, and main scale parameters are input in the platform model;

[0010] S2: based on S1, spatial velocity potential of flow field in the platform model is solved, mass matrix, damping matrix and platform stiffness matrix are obtained, frequency domain hydrodynamic coefficients and motion response amplitude RAO of the platform model are obtained according to the mass matrix, the damping matrix and the platform stiffness matrix;

[0011] S3: physical attribute parameters of mooring and riser system are input in the platform model, a platform mooring system model is established, initialization is completed, and the initialized platform mooring system model is obtained;

[0012] S4: parameters are input in the platform model, and combined with the initialized platform mooring system model, the frequency domain hydrodynamic coefficients and the motion response amplitude RAO, each order wave force, mooring tension and riser action force suffered by the platform model under the initial time step are solved;

[0013] S5: based on each order wave force, mooring tension and riser action force in S4, platform coupling motion equation of the platform model not containing fluid action force in the moon pool is solved, and six-degree-of-freedom motion displacement of the platform model is obtained;

[0014] S6: based on the computational fluid dynamics method, a viscous three-dimensional numerical water pool is constructed, the calculation domain grid is divided, the overlapping grid area is specified, the spatial discrete format, the time discrete format and the velocity-pressure coupling algorithm of the finite volume method are defined, the boundary conditions are defined, and the initial flow field is completed;

[0015] S7: the six-degree-of-freedom motion displacement of the platform model is specified as the six-degree-of-freedom motion of the overlapping grid area;

[0016] S8: based on S6 and S7, the nonlinear motion of the water body in the moon pool is solved, parameters including fluid pressure are obtained, and pressure integration is performed on the inner wall of the moon pool to obtain the fluid action force in the moon pool;

[0017] S9: the next time step iteration is performed, S4 is repeated, the fluid action force in the moon pool calculated in S8 is added to the time domain motion equation of the moon pool and the platform coupling, the time domain motion equation of the moon pool and the platform coupling is solved, the platform displacement is obtained, and the iteration is repeated until the last step of time calculation is completed.

[0018] The hydrodynamic calculation method of the moon pool and the platform coupling, preferably, in S1, the three-dimensional potential flow theory assumes that the fluid is an ideal fluid with no viscosity, no rotation and no compressibility, and the main scale parameters include platform weight, gravity center and inertia radius.

[0019] The water dynamic force calculation method of the moon pool and the platform coupling, preferably, in S2, the space velocity potential of the flow field comprises an incident potential, a radiation potential and a diffraction potential, and specifically as follows:

[0020]

[0021] In the formula, is the total velocity potential; is the incident potential; is the radiation potential; is the diffraction potential; v j is the j-degree-of-freedom motion amplitude; j is the j-degree-of-freedom of the floating body. The water dynamic force calculation method of the moon pool and the platform coupling, preferably, in S6, the computational fluid dynamics method is a Reynolds-averaged Navier-Stokes equation method, and specifically as follows:

[0022]

[0023] In the formula, u i is the average velocity component; x i is the Cartesian coordinate value; t is time; p is pressure; μ is dynamic viscosity; μ' i , μ' j is the fluctuating velocity component. The water dynamic force calculation method of the moon pool and the platform coupling, preferably, in S6, the Reynolds-averaged Navier-Stokes equation is discretized by using a finite volume method, a second-order upwind discretization format is used for spatial discretization, an implicit unsteady second-order time format is used for time discretization, and a SIMPLE algorithm is used for velocity-pressure coupling calculation.

[0024] The water dynamic force calculation method of the moon pool and the platform coupling, preferably, in S6, the initialization of the flow field comprises the following specific steps:

[0025] A calculation domain of a viscous three-dimensional numerical water pool is constructed, a platform fixed wall boundary containing the moon pool is established, and a boundary condition of a solid wall boundary is set for the periphery of the numerical water pool;

[0026] A flow field characteristic of a free liquid surface is captured by using a fluid volume function VOF method;

[0027] A mesh division problem of a complex platform structure containing the moon pool is solved by using an overlapping grid method, information transmission between a moving region and a background grid is realized, and flow field initialization is completed.

[0028] The water dynamic force calculation method of the moon pool and the platform coupling, preferably, in S9, the action force in the moon pool obtained by calculation is added to a platform total time domain motion equation through coordinate system conversion, and a moon pool and platform coupling motion equation under a full time domain is established:

[0029]

[0030] wherein M and a ij are mass matrix and added mass matrix, respectively; X is displacement matrix; K is delay function matrix; C ij is hydrostatic restoring force matrix; τ is time delay integral variable; t is time; F wave (t) is first-order and second-order wave load, F wind (t) is wind load, F current (t) is flow load, F moor (t) is mooring force, F moonpool (t) is fluid force in moon pool.

[0031] The second aspect of the present application provides a device for calculating hydrodynamic force of a moon pool coupled with a platform, comprising:

[0032] A first processing unit is configured to establish a platform model without moon pool based on three-dimensional potential flow theory, set environmental parameters, divide surface boundary grid of the platform model, and input main dimension parameters in the platform model;

[0033] A second processing unit is configured to obtain mass matrix, damping matrix, and platform stiffness matrix based on spatial velocity potential of flow field in the platform model solved by the first processing unit, and obtain frequency domain hydrodynamic coefficients and motion response amplitude (RAO) of the platform model according to the mass matrix, the damping matrix, and the platform stiffness matrix;

[0034] A third processing unit is configured to input physical property parameters of mooring and riser system in the platform model, establish a platform mooring system model, complete initialization, and obtain an initialized platform mooring system model;

[0035] A fourth processing unit is configured to input parameters in the platform model and combine the initialized platform mooring system model, the frequency domain hydrodynamic coefficients, and the motion response amplitude (RAO) to solve each order wave force, mooring tension, and riser force on the platform model at an initial time step;

[0036] A fifth processing unit is configured to solve platform coupling motion equation of the platform model without fluid force in moon pool based on each order wave force, mooring tension, and riser force in the fourth processing unit to obtain six-degree-of-freedom motion displacement of the platform model;

[0037] A sixth processing unit is configured to construct a viscous three-dimensional numerical water pool based on computational fluid dynamics method, divide calculation domain grid, specify overlapping grid area, define finite volume method spatial discretization format, time discretization format, and velocity-pressure coupling algorithm, define boundary conditions, and complete initialized flow field;

[0038] A seventh processing unit is configured to specify six-degree-of-freedom motion of the platform model as six-degree-of-freedom motion of the overlapping grid area;

[0039] An eighth processing unit is configured to solve the nonlinear motion of the water body in the moon pool based on the sixth processing unit and the seventh processing unit, to obtain parameters including fluid pressure, and to perform pressure integration on the inner wall of the moon pool to obtain fluid force acting on the moon pool;

[0040] A ninth processing unit is configured to perform next time step iteration, repeat the fourth processing unit, add the fluid force acting on the moon pool obtained by the eighth processing unit to the time-domain motion equation of the coupling of the moon pool and the platform, solve the time-domain motion equation of the coupling of the moon pool and the platform, and obtain platform displacement, and repeatedly iterate until the last step of time calculation is completed.

[0041] The third aspect of the present application provides a computer readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the steps of the hydrodynamic calculation method of the coupling of the moon pool and the platform according to any one of the above aspects.

[0042] The fourth aspect of the present application provides a computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the hydrodynamic calculation method of the coupling of the moon pool and the platform according to any one of the above aspects when executing the computer program.

[0043] The present application has the following advantages due to the above technical solutions:

[0044] 1. The present application combines the advantages of the computational fluid dynamics (CFD) method and the potential flow theory, and the method can solve the motion characteristics of the platform overall system under the coupling state of anchoring, riser, moon pool and the like, solve the problem that the CFD method is difficult to simultaneously solve the multi-scale model, and improve the overall calculation efficiency.

[0045] 2. The present application solves the complex dynamic response problem of the water body in the moon pool which cannot be considered by the existing linear potential flow theory, such as superposition of different motion types and modes, instantaneous rolling deformation of the free surface and vortex shedding near the wall, and can accurately predict the complex motion of the fluid in the moon pool and the force acting on the platform. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The flowchart of the hydrodynamic calculation method of the coupling of the moon pool and the platform provided by an embodiment of the present application is shown in the figure;

[0047] Figure 2 The schematic diagram of the platform overall system coupled by the mooring cable, the riser and the moon pool provided by the embodiment of the present application is shown in the figure;

[0048] Figure 3 The schematic diagram of the coupling calculation domain and boundary of the moon pool and the platform provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0049] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0050] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the common meaning understood by those skilled in the art. The terms "first", "second", "third", "fourth" and similar words used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar words mean that the elements or objects before the words cover the elements or objects listed after the words and their equivalents, without excluding other elements or objects. The terms "connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0051] In order to facilitate the description, spatial relative terms can be used in the description to describe the relationship of one element or feature relative to another element or feature as shown in the drawings, such as "inner", "outer", "inboard", "outboard", "under", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the drawings.

[0052] The existing computational fluid dynamics (CFD) numerical calculation method can only predict the motion and moon pool wave surface elevation in the case of a relatively simple platform system, cannot consider the coupling of complex systems such as anchoring, riser and moon pool, and has low calculation efficiency. The existing potential flow theory calculation method, the linear potential flow theory cannot consider the nonlinear characteristics of the fluid response in the moon pool, the prediction result may have large deviation, and the coupling hydrodynamic characteristics of the moon pool and the platform are unknown.

[0053] Based on the above technical problems, the present application provides a moon pool and platform coupling hydrodynamic calculation method, which combines viscous computational fluid dynamics and potential flow theory method, considers the complex motion characteristics of the fluid response in the moon pool, realizes the coupling calculation of the moon pool and the platform motion, and can effectively solve the nonlinear hydrodynamic problem of the coupling of the moon pool internal water body and the platform system.

[0054] As shown in Figure 1 The moon pool and platform coupling hydrodynamic calculation method provided by the present application comprises the following specific steps:

[0055] S1: Based on three-dimensional potential flow theory, assuming that the fluid is inviscid, irrotational and incompressible ideal fluid, a platform model excluding moon pool is established, environmental parameters such as water depth are set, platform surface boundary grid is divided, and main scale parameters such as platform weight, center of gravity, and inertia radius are input.

[0056] The space velocity potential in the flow field is divided into incident potential, radiation potential and diffraction potential:

[0057]

[0058] In the formula, is the total velocity potential; is the incident potential; is the radiation potential; is the diffraction potential;v j is the j degree of freedom motion amplitude; j is the j degree of freedom of the floating body. S2: Based on S1, the space velocity potential of the flow field in the platform model is solved by using the constant boundary element method, the mass matrix, the damping matrix, and the platform stiffness matrix are obtained, and the frequency domain hydrodynamic coefficients such as platform added mass and radiation damping and motion response amplitude RAO are obtained according to the mass matrix, the damping matrix, and the platform stiffness matrix.

[0059] S3: The coordinates of the fairlead and anchor point of the mooring system, the material, diameter, length, The main physical properties such as weight, stiffness, etc. are used to build the platform mooring system model; the water depth, wind load coefficient, flow load coefficient, hydrodynamic parameter, etc. of the mooring cable are input in the platform model, and the wave parameters of regular wave or irregular wave are input, including wave spectrum, period, wave height, etc.

[0060] S4: The hydrodynamic parameters are input in the platform model, and the initial platform mooring system model, the frequency domain hydrodynamic coefficients and the motion response amplitude RAO are combined to solve the wave forces, mooring tensions and riser forces of each order on the platform model at the initial time step.

[0061] S5: Based on the wave forces, mooring tensions and riser forces of each order in S4, the platform coupling motion equation of the platform model excluding the fluid force in the moon pool is solved, and the six degree of freedom motion displacement of the platform model is obtained.

[0062] S6: Based on the computational fluid dynamics method, a viscous three-dimensional numerical tank is constructed, the calculation domain grid is divided, the overlapping grid area is specified, the spatial discretization format, the time discretization format and the velocity-pressure coupling algorithm of the finite volume method are defined, and the boundary conditions are defined. Complete the initialization of the flow field.

[0063] The computational fluid dynamics method is to use the Reynolds averaged Navier-Stokes equation method, which is as follows:

[0064]

[0065] In the formula, u iis the mean velocity component; x i is the Cartesian coordinate value; t is the time; p is the pressure; μ is the dynamic viscosity; μ i j is the fluctuating velocity component. In S6, the Reynolds-averaged Navier-Stokes equations are discretized by the finite volume method, the spatial discretization scheme is the second-order upwind scheme, the time discretization scheme is the implicit unsteady second-order time scheme, and the velocity-pressure coupling calculation is performed by the SIMPLE algorithm.

[0066] The flow field initialization includes the following steps:

[0067] A calculation domain of a viscous three-dimensional numerical water pool is constructed, a platform fixed wall boundary containing a moon pool is established, and boundary conditions around the numerical water pool are set as fixed wall boundaries.

[0068] The VOF method is used to capture the flow field characteristics of the free surface.

[0069] The overlapping grid method is used to solve the grid division problem of the complex platform structure containing the moon pool, and the motion Information transfer between the regional and background grids, complete the initialization of the flow field.

[0070] S7: The six-degree-of-freedom motion displacement of the platform model is specified as the six-degree-of-freedom motion of the overlapping grid region.

[0071] S8: Based on S6 and S7, the nonlinear motion of the water body in the moon pool is solved to obtain parameters including fluid pressure, and the pressure integral on the inner wall of the moon pool is performed to obtain the fluid force acting on the moon pool;

[0072] S9: The next time step iteration is performed, S4 is repeated, the fluid force in the moon pool calculated in S8 is added to the time-domain motion equation of the moon pool and the platform coupling, the time-domain motion equation of the moon pool and the platform coupling is solved, and the platform displacement is obtained. Repeat the iteration until the last step of time calculation is completed.

[0073] In S9, the calculated action force in the moon pool is added to the total time-domain motion equation of the platform through coordinate system conversion, and the coupling motion equation of the moon pool and the platform under the whole time domain is established:

[0074]

[0075] In the formula, M and a ij are the mass matrix and the added mass matrix, respectively; X is the displacement matrix; K is the delay function matrix; C ij is the static water restoring force matrix; τ is the time delay integral variable; t is the time; F wave (t) is the first-order and second-order wave load, F wind (t) is the wind load, F current (t) is the flow load, F moor (t) is the mooring force, F​moonpool (t) is the fluid force in the moon pool.

[0076] The second aspect of the present application provides a device for calculating hydrodynamic force of a moon pool and a platform coupling, comprising:

[0077] A first processing unit is configured to establish a platform model without a moon pool based on three-dimensional potential flow theory, set environmental parameters, divide surface boundary grids of the platform model, and input main scale parameters in the platform model;

[0078] A second processing unit is configured to obtain a mass matrix, a damping matrix, and a platform stiffness matrix based on the spatial velocity potential of the flow field in the platform model solved by the first processing unit, and obtain frequency domain hydrodynamic coefficients and motion response amplitude (RAO) of the platform model according to the mass matrix, the damping matrix, and the platform stiffness matrix;

[0079] A third processing unit is configured to input physical property parameters of a mooring and riser system in the platform model, establish a platform mooring system model, complete initialization, and obtain an initialized platform mooring system model;

[0080] A fourth processing unit is configured to input parameters in the platform model and combine the initialized platform mooring system model, the frequency domain hydrodynamic coefficients, and the motion response amplitude (RAO) to solve wave forces, mooring tensions, and riser forces of each order on the platform model at an initial time step;

[0081] A fifth processing unit is configured to solve a platform coupling motion equation of the platform model without fluid force in the moon pool based on the wave forces, the mooring tensions, and the riser forces of each order in the fourth processing unit, and obtain six-degree-of-freedom motion displacement of the platform model;

[0082] A sixth processing unit is configured to construct a viscous three-dimensional numerical water pool based on a computational fluid dynamics method, divide a calculation domain grid, specify an overlapping grid area, define a finite volume method spatial discretization format, a time discretization format, and a velocity-pressure coupling algorithm, define boundary conditions, and complete an initialized flow field;

[0083] A seventh processing unit is configured to specify the six-degree-of-freedom motion displacement of the platform model as the six-degree-of-freedom motion of the overlapping grid area;

[0084] An eighth processing unit is configured to solve nonlinear motion of water in the moon pool based on the sixth processing unit and the seventh processing unit, obtain parameters including fluid pressure, and perform pressure integration on the inner wall of the moon pool to obtain fluid force in the moon pool;

[0085] The ninth processing unit is configured to perform the next time step iteration, repeat the fourth processing unit, add the moon pool internal fluid force calculated by the eighth processing unit to the time domain motion equation of the moon pool and the platform coupling, solve the time domain motion equation of the moon pool and the platform coupling, and obtain the platform displacement, and iteratively repeat until the last step of time calculation is completed.

[0086] The third aspect of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the steps of the hydrodynamic calculation method of the moon pool and the platform coupling according to any one of the above aspects.

[0087] The fourth aspect of the present application provides a computer device, which comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the hydrodynamic calculation method of the moon pool and the platform coupling according to any one of the above aspects when executing the computer program.

[0088] The present application is described in terms of flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to the specific implementations. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0089] These computer program instructions can also be stored in a computer readable memory capable of directing a computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer readable memory produce a product including instruction means, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0090] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0091] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A hydrodynamic calculation method for the coupling of a moon pool and a platform, characterized in that, include: S1: Based on the three-dimensional potential flow theory, establish a platform model that does not include the moon pool, set environmental parameters, divide the surface boundary mesh of the platform model, and input the principal scale parameters into the platform model; S2: Based on S1, solve the spatial velocity potential of the flow field in the platform model to obtain the mass matrix, damping matrix, and platform stiffness matrix. Based on the mass matrix, damping matrix, and platform stiffness matrix, obtain the frequency domain hydrodynamic coefficients and motion response amplitude RAO of the platform model. S3: Input the physical property parameters of the mooring and riser systems into the platform model, establish the platform mooring system model, complete the initialization, and obtain the initialized platform mooring system model; S4: Input hydrodynamic parameters into the platform model and combine them with the initial platform mooring system model, frequency domain hydrodynamic coefficients and motion response amplitude RAO to solve the wave forces, mooring tensions and riser forces acting on the platform model at the initial time step. S5: Based on the wave forces, mooring tensions and riser forces in S4, solve the platform coupled motion equations of the platform model that do not include the fluid forces in the moon pool, and obtain the six-degree-of-freedom motion displacement of the platform model. S6: Based on computational fluid dynamics, construct a three-dimensional numerical water tank for viscous flow, divide the computational domain into grids, specify overlapping grid regions, define the spatial discretization scheme, time discretization scheme, and velocity-pressure coupling algorithm of the finite volume method, define boundary conditions, and complete the initialization of the flow field; S7: Specify the six-degree-of-freedom motion displacement of the platform model as the six-degree-of-freedom motion of the overlapping mesh region; S8: Based on S6 and S7, solve the nonlinear motion of the water in the lunar pool to obtain parameters including fluid pressure, and perform pressure integration on the inner wall of the lunar pool to obtain the fluid force in the lunar pool. S9: Proceed to the next time step iteration, repeat S4, and add the fluid force in the moon pool calculated in S8 to the time-domain motion equation of the moon pool and platform coupling. Solve the time-domain motion equation of the moon pool and platform coupling to obtain the platform displacement. Iterate repeatedly until the last time calculation is completed.

2. The hydrodynamic calculation method for the coupling of the moon pool and the platform according to claim 1, characterized in that, In S1, the three-dimensional potential flow theory assumes that the fluid is an ideal fluid that is inviscid, irrotational, and incompressible. The principal scale parameters include the platform weight, center of gravity, and radius of inertia.

3. The hydrodynamic calculation method for the coupling of the moon pool and the platform according to claim 1, characterized in that, In S2, the spatial velocity potential of the flow field includes the incident potential, the radiation potential, and the diffraction potential, as detailed below: In the formula, The total velocity potential; For the incident potential; Radiation potential; For diffraction potential; v j Let be the amplitude of motion for degree j; j is the j-degree of freedom of the floating body.

4. The hydrodynamic calculation method for the coupling of the moon pool and the platform according to claim 1, characterized in that, In S6, the computational fluid dynamics method employs the Reynolds-averaged Navier-Stokes equations, as detailed below: In the formula, u i x represents the average velocity component; i t represents the Cartesian coordinates; t represents time. p is pressure; μ is dynamic viscosity; μ' i ,μ' j Pulsating velocity component.

5. The hydrodynamic calculation method for the coupling of the moon pool and the platform according to claim 4, characterized in that, In S6, the Reynolds-averaged Navier-Stokes equations are discretized using the finite volume method. The spatial discretization scheme is a second-order upwind discretization scheme, the time discretization scheme is an implicit unsteady second-order time scheme, and the velocity-pressure coupling calculation uses the SIMPLE algorithm.

6. The hydrodynamic calculation method for the coupling of the moon pool and the platform according to claim 5, characterized in that, In S6, initializing the flow field includes the following specific steps: Construct the computational domain of a viscous flow three-dimensional numerical water tank, establish a platform solid-wall boundary containing the moon pool, and set the boundary conditions around the numerical water tank as solid-wall boundaries. The fluid volume function (VOF) method is used to capture the flow field characteristics of the free liquid surface; An overlapping mesh method is adopted to solve the mesh generation problem of complex platform structures containing moon pools, realize the information transfer between the moving region and the background mesh, and complete the flow field initialization.

7. The hydrodynamic calculation method for the coupling of the moon pool and the platform according to claim 1, characterized in that, In S9, the calculated forces within the lunar pool are added to the overall time-domain motion equations of the platform through coordinate system transformation, establishing the coupled motion equations of the lunar pool and the platform in the entire time domain: In the formula, M and a ij These are the mass matrix and the additional mass matrix, respectively; X is the displacement matrix; K is the delay function matrix; C ij Let τ be the still water restoring force matrix; τ be the time-delay integral variable; t represents time; F wave (t) represents the first-order and second-order wave loads, F wind (t) represents the wind load, F current (t) represents the flow load, F moor (t) represents the mooring force, F moonpool (t) represents the fluid force within the lunar pool.

8. A hydrodynamic calculation device coupling a moon pool and a platform, characterized in that, include: The first processing unit is used to establish a platform model without the moon pool based on the three-dimensional potential flow theory, set environmental parameters, divide the surface boundary mesh of the platform model, and input the principal scale parameters into the platform model. The second processing unit is used to solve the spatial velocity potential of the flow field in the platform model based on the first processing unit, and obtain the mass matrix, damping matrix, and platform stiffness matrix. Based on the mass matrix, damping matrix, and platform stiffness matrix, the frequency domain hydrodynamic coefficients and motion response amplitude RAO of the platform model are obtained. The third processing unit is used to input the physical property parameters of the mooring and riser systems into the platform model, establish the platform mooring system model, complete the initialization, and obtain the initialized platform mooring system model. The fourth processing unit is used to input parameters into the platform model and combine them with the initial platform mooring system model, frequency domain hydrodynamic coefficients and motion response amplitude RAO to solve the wave forces, mooring tensions and riser forces acting on the platform model at the initial time step. The fifth processing unit is used to solve the platform coupled motion equations of the platform model that do not include the fluid forces in the moon pool, based on the wave forces, mooring tensions and riser forces of each order in the fourth processing unit, and to obtain the six-degree-of-freedom motion displacement of the platform model. The sixth processing unit is used to construct a three-dimensional numerical water tank for viscous flow based on computational fluid dynamics methods, divide the computational domain into grids, specify overlapping grid regions, define the spatial discretization scheme, time discretization scheme, and velocity-pressure coupling algorithm of the finite volume method, define boundary conditions, and complete the initialization of the flow field. The seventh processing unit is used to specify the six-degree-of-freedom motion displacement of the platform model as the six-degree-of-freedom motion of the overlapping mesh region; The eighth processing unit is used to solve the nonlinear motion of the water in the lunar pool based on the sixth and seventh processing units, obtain parameters including fluid pressure, and perform pressure integration on the inner wall of the lunar pool to obtain the fluid force in the lunar pool. The ninth processing unit is used to perform the next time step iteration. It repeats the fourth processing unit and adds the fluid force in the moon pool calculated by the eighth processing unit to the time-domain motion equation of the moon pool and platform coupling. It solves the time-domain motion equation of the moon pool and platform coupling to obtain the platform displacement. It iterates repeatedly until the last time calculation is completed.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the hydrodynamic calculation method for coupling the moon pool and the platform as described in any one of claims 1-7.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the hydrodynamic calculation method for coupling the moon pool and the platform as described in any one of claims 1-7.

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