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86 results about "Continuity equation" patented technology

A continuity equation in physics is an equation that describes the transport of some quantity. It is particularly simple and powerful when applied to a conserved quantity, but it can be generalized to apply to any extensive quantity. Since mass, energy, momentum, electric charge and other natural quantities are conserved under their respective appropriate conditions, a variety of physical phenomena may be described using continuity equations.

Liquid cooling device and preparation method and application thereof

The invention belongs to the related technical field of heat dissipation of electronic equipment, and discloses a liquid cooling device and a preparation method and application thereof, and the method comprises the steps: S1, enabling a control equation of the liquid cooling device to be equivalent to a continuity equation, an N-S equation and a heat transfer equation based on equivalent parameters; s2, taking the minimum average temperature and energy dissipation of the whole design domain of the liquid cooling device as a target function, taking the volume fraction of the fluid domain as a constraint condition, and constructing a topological optimization model based on a continuity equation, an N-S equation and a heat transfer equation; s3, an optimization solver is adopted to carry out iterative solution on the topological optimization model, whether a result meets a convergence condition or not is judged, if yes, a topological structure is output, and the step S4 is executed; otherwise, updating the design variable of the topological optimization model, and turning to the step S1; and S4, the three-dimensional model of the liquid cooling device is corrected based on the obtained topological structure, and then blowing forming is carried out based on the corrected three-dimensional model to obtain the liquid cooling device. According to the invention, the cost is reduced.
Owner:HUAZHONG UNIV OF SCI & TECH

Simulation method, device and equipment for predicting flow and deformation of porous medium and medium

The invention discloses a simulation method, device and equipment for predicting flow and deformation of a porous medium and the medium. The method comprises the steps that a computational domain is selected, a corresponding computational grid is generated, and porosity initialization is conducted on the computational domain; determining a time step length and a discrete format, and setting a non-uniform factor to solve a control equation set which comprises a continuity equation, a fluid dynamics equation, a skeleton mechanics equation and a porosity updating equation; and analyzing and displaying a solving result. According to the porous medium flow and deformation simulation method independent of hypothesis and empirical parameters, the method is based on the basic principle of the microcosmic fluid-solid coupling effect, a porous medium fluid-solid coupling body kinetic equation is adopted, the situation that a traditional modeling method depends on volume averaging hypothesis and depends on a multi-phase interaction model is avoided, and the modeling efficiency is improved. The method has cross-scale applicability, and provides a new theoretical basis and prediction means for the development of technologies related to porous medium multiphase dynamics and multi-field coupling problems.
Owner:INST OF ROCK & SOIL MECHANICS CHINESE ACAD OF SCI

Fluid-structure interaction numerical simulation method, device, equipment and medium

The invention discloses a fluid-structure interaction numerical simulation method, device and equipment and a medium, and the method comprises the steps: selecting a fluid-structure interaction computational domain, generating a computational grid, and marking the computational domain according to fluid and solid distribution information; determining a solving time step length and a discrete format, and selecting a control equation set for solving, the control equation set comprising a continuity equation, a fluid dynamics equation, a solid dynamics equation and a phase transfer equation; and analyzing and displaying a solving result. According to the efficient fluid-solid coupling numerical simulation method, global unified calculation is achieved, explicit fluid-solid decoupling is not needed, a global fluid-solid coupling body kinetic equation is adopted, errors caused by fluid-solid decoupling processing in a traditional split-phase solving method are avoided, and the method does not need to depend on and repeatedly generate a complex body-fitted grid; the control equation is based on each phase conservation equation on a physical continuous domain and realizes interphase accurate association through an interface continuity condition, and the fluid-solid coupling problem can be accurately and quickly solved.
Owner:INST OF ROCK & SOIL MECHANICS CHINESE ACAD OF SCI

Water and sediment scheduling and water quality scene prediction method for reservoir area in high-cold area

The invention relates to the technical field of environmental governance, and discloses an alpine region reservoir area water and sediment scheduling and water quality scenario prediction method comprising the following steps: river network segmentation and node classification; embedding ice kinetic parameters; transporting and correcting low-temperature silt; carrying out low-temperature adaptation on water quality parameters; performing dynamic boundary transfer and joint solution; and carrying out synchronous real-time iterative calculation. According to the method, ice kinetic parameters are embedded in a one-dimensional Saint-Venant equation, and the coupling relation between the thickness of the ice cover and the hydraulic element is dynamically solved by correcting the effective cross-section area in a continuous equation and the friction gradient in a momentum equation and adopting an iterative algorithm. Therefore, the water level fluctuation in the ice dam forming and outburst process is accurately described, and the problem that an existing model is insufficient in response to ice period hydraulic sudden change is solved.
Owner:LANZHOU UNIVERSITY OF TECHNOLOGY

Cooling element of precision worm wheel gear grinding machine and its multi-objective thermal-fluid topology design optimization method

The present invention discloses a multi-objective thermal-fluid topological design optimization method for the cooling element of a precision gear grinding machine tool, comprising the following steps: Step 1: Define the design domain: Expand the cooling element into a plane, define a two-dimensional design domain representing the cooling element's geometric structure, and discretize it using the finite element method; Step 2: Numerical modeling: Model the cooling element as a porous medium; Under the conditions of laminar incompressible flow, the fluid dynamics are governed by the dimensionless forms of the continuity equation and the momentum equation; The fluid-solid coupled heat transfer model is governed by the dimensionless energy conservation equation; Step 3: Construct an objective function: The optimization objective is defined as a weighted function of heat transfer and fluid dissipated power, and a fluid-solid heat transfer topological optimization model is constructed; Step 4: Solve the objective function; Step 5: Restore the shape and structure of the cooling element. The present invention also discloses a precision gear grinding machine tool and a cooling element.
Owner:CHONGQING UNIV

System and method for depth-based flow metering

A system and method for measuring or for estimating flow or flowrate of a fluid, including wastewater inflow or infiltration, using non-contact depth-based flow measurement, including: receiving a depth sensor signal from an ultrasonic depth sensor positionable over a manhole channel above an outgoing pipe's crown; receiving a temperature signal from a temperature sensor positionable within the manhole channel; receiving one or more data input signals; calculating a distance to a surface of the fluid based on the received depth sensor signal; and determining a depth of the fluid in the manhole channel based on the calculated distance. Flow velocity may be calculated using Manning's equation or the Hazen-Williams equation, with flow rate subsequently determined using the continuity equation. Alternatively, flow velocity and flow rate may be estimated using a machine learning model trained on simulated or historical time-series data of flow rate, flow velocity, and flow depth, along with pipe attributes, to generate real-time flow estimates based on current and prior flow depth measurements.
Owner:HAMPTON ROADS SANITATION DISTRICT

Seepage prediction method based on foam oil evolution and local time step encryption

The invention relates to the technical field of foam oil evolution, in particular to a seepage prediction method based on foam oil evolution and local time step encryption, which comprises the following steps: constructing a reservoir geological conceptual model by using rock physical parameters, fluid characteristic parameters and reservoir basic data; defining CO2 foam oil reaction and reaction parameters of the reservoir geological conceptual model in the reservoir geological conceptual model; setting phase permeability parameters of the three-phase fluid; well group parameters are imported, and a production system is determined; setting initial parameters of the reservoir geological conceptual model; solving a pressure field of each step in an allowable material balance error range based on material balance, a continuity equation and a phase state balance equation of the seepage field; and adjusting local encryption time steps, and optimizing model numerical calculation parameters. The method solves the problem that the traditional method is difficult to consider the generation, breaking and phase change of each substance, so that the substance balance error is large.
Owner:CHANGZHOU UNIV

Water recession model establishment method and system based on long-distance pressure pipeline

PendingCN120671596ADesign optimisation/simulationWater withdrawalStructural engineering
The invention relates to the technical field of numerical simulation calculation of water conveyance projects, in particular to a water recession model establishment method and system based on a long-distance pressure pipeline. The method comprises the steps that a rigid water column model is constructed based on deformation of a motion equation and a continuity equation in the non-constant flowing process of fluid in a pressure pipeline, and a water column flow velocity equation and a water column length equation are established to describe liquid phase changes in the non-air-valve water recession process by combining change analysis of hydraulic parameters in the pressure pipeline on the time scale. The pressure intensity in a hollow pipe section at the upstream end of a pressure pipeline without an air valve is analyzed to describe the volume change in the hollow pipe section to construct an air-valve-free water recession model, the change of gas parameters of air passing through the air valve in the hollow pipe section at the upstream end of the pressure pipeline on the time scale is analyzed to construct an air-valve water recession model, and simulation is solved through the model. And predicting the change trend and fluctuation condition of the pressure water head in the upstream end hollow pipe section in the water recession process of the pressure pipeline. The method can accurately predict the recession process of the long-distance water delivery pipeline.
Owner:XIAN UNIV OF TECH +1

Unconventional oil and gas reservoir heat-fluid-solid coupling numerical simulation method and system

The invention provides an unconventional oil and gas reservoir heat-fluid-solid coupling numerical simulation method and system. The method comprises the steps that a multiphase numerical model of a coupling temperature field, a seepage field and a stress field is built; the multiphase numerical model is integrated with a Cahn-Hilliard equation, a heat conduction equation, a continuity equation, a Navier-Stokes equation and a mechanical equilibrium equation; determining a model computational domain of the multiphase numerical model; performing grid discretization processing on the model calculation domain and performing grid refinement processing on the peripheries of the mass flow inlet and the pressure outlet to obtain a plurality of grid units; inputting the environmental parameters and the initial condition parameters into the multiphase numerical model, controlling the multiphase numerical model to perform discrete calculation in each grid unit, judging whether a convergence condition is met or not, and if yes, updating the physical property parameters of the multiphase fluid according to the current temperature and pressure, and outputting a numerical simulation result of the unconventional oil and gas reservoir. According to the invention, the productivity prediction deviation can be reduced.
Owner:OIL & GAS SURVEY CGS

Method, device and equipment for analyzing pressure drop of serpentine well

The invention relates to the technical field of oil and gas field development, and provides a method, device and equipment for analyzing the pressure drop of a serpentine well. The method comprises the steps that micro-arc section extraction and basic parameter setting are conducted on the serpentine well; according to the set basic parameters, micro-arc section flow characteristic analysis is conducted, and in combination with a fluid continuity equation and a momentum conservation equation, a serpentine well horizontal section single-phase pressure drop gradient prediction model is established; predicting pressure gradient data in the serpentine well by using the serpentine well horizontal section single-phase pressure drop gradient prediction model; and the serpentine well is set to adopt fixed bottom hole flowing pressure production, and the pressure drop of the horizontal section of the serpentine well is calculated by adopting a pressure drop superposition method according to the pressure gradient data in the serpentine well. According to the method, the influence of the geometrical morphology change of the shaft on fluid flow is effectively described, especially the continuous change of the gravity component along with the hole drift angle, and the inherent defect that a traditional model simplifies the shaft into horizontal flow is overcome.
Owner:CHANGZHOU UNIV

Method for calculating critical submerged depth of side-inlet based on CSSS method

The application discloses a method for calculating critical submerged water depth of a side-type water inlet based on a CSSS method. A point sink spherical critical surface model is constructed, and a conservation relationship between an effective working area and a radial flow velocity is established based on a continuity equation. For complex boundary working conditions, a dimensionless criterion is introduced to determine the effectiveness of the spherical assumption, and when the spherical assumption is invalid, an anisotropic ellipsoid correction is started, and a coordinate stretching equivalent method is used to calculate a limited effective area. A physical correction coefficient is constructed by using a potential flow geometric component and a dynamic loss component to replace pure statistical regression. A dynamic safety margin is calculated in combination with a vortex evolution time scale. The application solves the problem of prediction distortion of the critical water depth under a complex flow field, and improves the physical precision and operation safety of engineering design.
Owner:NANJING HYDRAULIC RES INST

Method for determining volume evolution model of Newtonian fluid liquid film under action of shear airflow

The invention relates to the technical field of fluid mechanics, and discloses a method for determining a volume evolution model of a Newtonian fluid liquid film under the action of shear airflow, and the method comprises the following steps: determining the thickness of the liquid film; determining an equilibrium equation based on set conditions; determining an expression of shear force of the liquid film surface according to the liquid film thickness and the liquid film surface speed; determining an expression of shearing force of the shearing airflow to the liquid film; substituting the two expressions into an equilibrium equation to obtain a liquid film surface velocity equation; determining a liquid membrane continuity equation and a liquid membrane internal velocity equation; substituting the liquid film internal velocity equation and the liquid film surface velocity equation into a liquid film continuity equation to solve the time evolution process of the liquid film, and obtaining differential equations of liquid film volume evolution under the action of uniformly accelerated shear airflow and uniform shear airflow, so as to construct a model; the model has high accuracy for the volume evolution rule of the Newtonian fluid membrane.
Owner:BEIHANG UNIV +1

A method for constructing a ship pressure field model in shallow water waves and a target determination method

The present invention provides a method for constructing a ship pressure field model in shallow water waves and a target determination method. The method uses ideal incompressible fluid theory to establish the continuity equation and momentum equation satisfied by the ship in the geodetic coordinate system. Based on the shallow water assumption, a depth-averaged perturbation velocity potential is introduced. Combined with the bottom boundary conditions and the free surface boundary conditions, a flow field control equation expressed by the depth-averaged perturbation velocity potential is constructed. The wave source term within the domain is set according to the wave environment, and the moving pressure term is set according to the ship type. The wave source term within the domain and the moving pressure term are substituted into the flow field control equation to simulate the effect of the surface ship disturbance in the wave environment, thereby obtaining the ship pressure field control equation. Based on the ship pressure field control equation, the ship pressure field model is constructed in combination with the initial and boundary conditions of the flow field, as well as the relationship between the flow field pressure and velocity potential. The model is adapted to rapidly calculate the pressure field under different environments, thereby improving the prediction efficiency of the ship pressure field signal.
Owner:NAVAL UNIV OF ENG PLA

Filling pipeline resistance loss value calculation method, product, medium, and device

The present invention relates to the technical field of filling mining. Disclosed are a filling pipeline resistance loss value calculation method, a product, a medium, and a device. The method comprises: providing a plurality of pressure sensors on a filling pipeline and acquiring detected pressure data; on the basis of the pressure data, determining the flow velocity of a fluid at each pressure sensor of the filling pipeline using a continuity equation and momentum equation of fluid mechanics; calculating the Reynolds number of the fluid at each pressure sensor on the basis of the flow velocity of the fluid at each pressure sensor; dividing the filling pipeline into a stable flow pipeline and an unstable flow pipeline by means of the Reynolds number, and calculating the length of the unstable flow pipeline; calculating the frictional resistance loss of the filling pipeline on the basis of the length of the unstable flow pipeline; and calculating the resistance loss value of the filling pipeline on the basis of the frictional resistance loss. The filling pipeline resistance loss value calculation method, the product, the medium and the device provided by the present invention can effectively improve the calculation accuracy of the resistance loss value of the filling pipeline.
Owner:NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY

A method for simulating typhoon-induced debris flow motion considering spatiotemporal rainfall processes

The present invention provides a method for simulating the movement of typhoon-storm debris flow considering the spatiotemporal rainfall process, which iteratively performs the following calculations until the convergence condition is met: decomposing the average mud depth increment of the continuity equation into a mass flux term and a rainfall intrusion term, wherein: the mass flux term calculates the contribution of fluid movement to mud depth through divergence; the rainfall intrusion term is calculated through the spatiotemporal rainfall distribution function. q w Dynamically correct mud depth; calculate the volume concentration of the current time step based on the updated mud depth distribution, and dynamically correct the turbulent resistance coefficient of the rheological model through an exponential function according to the volume concentration; calculate the debris flow friction resistance based on the corrected rheological model, solve the momentum equation, drive the SPH particle motion, and output the spatiotemporal evolution results.
Owner:FUZHOU UNIV

A method and system for constructing a digital twin model of a gated water network

ActiveCN117592257BStream flowWater flow
The application discloses a kind of construction method and system of gate control water network digital twinborn model, including using Preissmann four-point implicit difference format to the conversion of the continuity equation and momentum equation of St.Venant equation group;Channel water conveyance internal compatibility condition equation is constructed, and constant flow and non-constant flow equation in water network water conveyance are established, according to the external boundary condition of the water network channel set, calculate water network flow state;Internal compatibility condition equation is constructed at the branch point of water network, according to the internal compatibility condition equation of gate in water network channel, calculate the flow of regulating gate;The water network model of the application is compared and verified with physical model test, prototype observation experimental data, and further parameter adjustment is satisfied to water level flow accurate simulation requirement.The application accurately and practically reflects the running state of water network in virtual state space model, and can solve the state simulation and accurate prediction problem of gate control water network under various complex operating conditions.
Owner:CHINA INST OF WATER RESOURCES & HYDROPOWER RES

A simulation method for retaining ring structure in chemical mechanical polishing process

The present invention provides a simulation method for a retaining ring structure in a chemical mechanical polishing process, comprising constructing a CFD model of the chemical mechanical polishing process, dividing a fluid region into discrete grids, wherein the grids are non-repetitive control volumes, and within each control volume, using a momentum equation, a continuity equation, and a VOF model to control the motion of the polishing liquid fluid, and a DPM model to control the motion of the abrasive, integrating the momentum equation, the continuity equation, and the VOF model for each control volume to obtain a discrete equation, solving the discrete equation to obtain simulation data, the simulation data including abrasive motion data, plotting the abrasive distribution and the abrasive aggregation state on the polishing pad and / or the wafer edge based on the abrasive motion data, and having the beneficial effects of visualizing the polishing liquid / abrasive flow through a finite element method, helping to understand the influence of the retaining ring on the polishing liquid flow, providing a retaining ring structure improvement to solve wafer edge over-polishing, conforming to actual production processes, and having high simulation accuracy.
Owner:SHANGHAI INST OF IC MATERIALS

Equivalent inertia correction method and device for lumped parameter model of gas pipeline

This application relates to the field of gas transportation technology, and provides an equivalent inertia correction method and apparatus for a lumped parameter model of a gas pipeline. The method includes: generating a lumped parameter model of the gas pipeline based on the continuity equation and momentum equation of a one-dimensional compressible gas; generating an equivalent inertia factor based on the equation of state of a real gas under isothermal conditions; wherein the equivalent inertia factor characterizes the nonlinear sensitivity of the compressibility factor of the real gas to pressure; correcting the equivalent inertia of the lumped parameter model based on the equivalent inertia factor; and updating the boundary values ​​of the lumped parameter model after correction based on the fluid sound velocity under the current operating conditions of the gas pipeline and the pipeline length constraint when a system disturbance occurs. The method provided in this application effectively compensates for the inertial distortion caused by lumped averaging of material properties and solves the global phase shift problem under complex operating conditions.
Owner:CHINA UNIV OF PETROLEUM (BEIJING)

Cavitation numerical simulation method based on consideration of multiphase flow shear state

The invention relates to a cavitation numerical simulation method based on consideration of a multiphase flow shear state, and the method comprises the steps: initializing basic parameters of a navigation body, the basic parameters including the shape, the length, the underwater navigation speed, the global cavitation number and the like; constructing a mathematical model based on the preprocessing matrix, wherein the mathematical model based on the preprocessing matrix comprises a continuous equation, a momentum equation, a component transport equation based on cavitation vapor phase volume fraction, a turbulence model equation and a cavitation model considering a multiphase flow shear state; constructing a flux calculation model adopting a windward format; constructing a grid for the wall surface of the navigation body; initializing flow field setting for the navigation body; and based on the basic parameters of the navigation body, the mathematical model based on the preprocessing matrix, the flux calculation model, the grid constructed for the wall surface of the navigation body and the flow field setting initialized for the navigation body, carrying out cavitation numerical simulation calculation on the navigation body.
Owner:CHINA ACAD OF AEROSPACE AERODYNAMICS

A method for analyzing dynamic mode and flow stability of double-box-girder flow field

ActiveCN120874179BAccurate numerical simulationSimulation results are reliableGeometric CADSustainable transportationBridge engineeringComputational model
The application discloses a kind of double box girder flow field dynamics modal and flow stability analysis method and system, belong to bridge engineering field.This method first establishes double box girder flow field model by computational fluid dynamics, solves the momentum equation and continuity equation of two-dimensional incompressible flow;Dynamic modal decomposition is carried out again, and eigenvalue, characteristic mode and other information are obtained;Finally, based on linear stability theory, the flow field component is expressed as the sum of steady-state solution and disturbance term, and the global linear flow stability equation is obtained by substituting into the equation, and the flow stability is analyzed by discrete.This method can accurately extract the modal characteristics of each order, providing a scientific basis for wind-induced vibration analysis of double box girder, and has important application value.The method of the application occupies less computing resources, has high numerical accuracy, and can be further expanded to higher precision calculation model according to computing resources, and is suitable for application in actual bridge engineering.
Owner:HARBIN INST OF TECH

An unconventional oil and gas reservoir thermal fluid-structure coupling numerical simulation method and system

The application provides an unconventional oil and gas reservoir thermal fluid-solid coupling numerical simulation method and system, and the method comprises the following steps: constructing a multiphase numerical model coupling a temperature field, a seepage field and a stress field; the multiphase numerical model integrates a Cahn-Hilliard equation, a heat conduction equation, a continuity equation, a Navier-Stokes equation and a mechanical equilibrium equation; determining a model calculation domain of the multiphase numerical model; performing grid discretization processing on the model calculation domain and performing grid refinement processing on the periphery of a mass flow inlet and a pressure outlet, thereby obtaining a plurality of grid units; inputting environmental parameters and initial condition parameters into the multiphase numerical model, controlling the multiphase numerical model to perform discrete calculation in each grid unit, judging whether a convergence condition is met, if the convergence condition is met, updating physical property parameters of a multiphase fluid according to a current temperature and pressure, and outputting a numerical simulation result of the unconventional oil and gas reservoir. The application can reduce the production capacity prediction deviation.
Owner:OIL & GAS SURVEY CGS

A method for predicting the amount of internal erosion and resuspension of seafloor sediments under wave action

The present invention provides a method for evaluating and predicting the amount of internal erosion and resuspension of seabed sediments under wave action. Based on the mass conservation equation for sediment particles, the erosion constitutive equation, and the seepage continuity equation, this method considers the impact of the accumulation of seabed pore-water pressure under wave action on the internal erosion process of sediments. It also considers the impact of changes in the physical properties of seabed soil caused by internal erosion on the development of the cumulative pore-water pressure of the seabed. A coupled mathematical model of the cumulative response of the seabed under wave action and internal erosion is constructed. The model is solved using the finite element method to obtain the development and changes in the cumulative pore-water pressure, porosity, volume concentration of suspended fine particles, and the mass of eroded fine particles. The present invention quantitatively assesses the mass of fine particles within seabed sediments that migrate outward with seepage under wave action, as well as the spatiotemporal evolution characteristics and patterns of the internal erosion process of sediments. This allows for quantitative prediction and analysis of seabed stability and the internal erosion and resuspension characteristics of seabed sediments.
Owner:OCEAN UNIV OF CHINA

Numerical simulation method for propagation characteristics before and after atmospheric breakdown of high-power microwave

The invention belongs to the technical field of radio wave propagation, and particularly discloses a numerical simulation method for propagation characteristics before and after atmospheric breakdown of high-power microwaves. The electron fluid model comprises a Maxwell equation set, an electron density continuity equation, an electron fluid momentum conservation equation and an electron fluid energy equation, and the evolution process of an electromagnetic field, electron density and electron energy before and after high-power microwave atmospheric breakdown can be calculated by solving the improved electron fluid model. According to the method, a more accurate transport coefficient is adopted according to different atmospheric pressures and initial electron densities, so that the simulation precision can be greatly improved; according to the method, a three-dimensional electromagnetic propagation problem can be converted into a quasi-two-dimensional problem, so that the simulation time is greatly shortened, and the computer memory is saved.
Owner:ANHUI UNIV

Seismic wave dispersion and attenuation prediction method and related equipment

The invention provides a seismic wave dispersion and attenuation prediction method and related equipment, and relates to the field of geophysical fluctuation induced fluid flow. The method comprises the steps that based on the bubble vibration theory and a pore fluid seepage continuity equation, a target elastic modulus is obtained, and the target elastic modulus is an elastic modulus obtained after bubble vibration correction is added; fusing the target elastic modulus into a strain energy function of a classical pore acoustic elasticity theory to obtain the strain energy function; deducing to obtain a wave equation of the fluid saturated porous medium containing a small amount of bubbles under the action of pressure by combining the strain energy function, the kinetic energy function and the dissipated energy function; and solving the simplified wave equation through the plane wave to obtain the seismic wave speed and attenuation. According to the embodiment of the invention, the frequency dispersion and attenuation of seismic waves can be accurately predicted within a certain effective pressure range.
Owner:CHINA UNIV OF PETROLEUM (EAST CHINA)

A Fluid-Structure Interaction Simulation Method for Immersed Boundaries Based on the Material Point Method and Position Dynamics

A fluid-structure interaction (FSI) simulation method for submerged boundaries based on the material point method and positional dynamics includes: a) solving for the solid state and calculating the Lagrangian elastic force of the solid; b) transferring the elastic force of the solid Lagrangian mesh vertices to the Eulerian background mesh; c) solving the Navier-Stokes fluid control equations and continuity equations on the Eulerian background mesh, feeding back the updated mesh flow field information to the particles, and updating the particle state synchronously; d) using a mapping matrix to map the positions of solid particles back to the vertices of the solid Lagrangian mesh, saving the vertex position data and fluid particle data for rendering output. This invention, through the above-mentioned hybrid Lagrangian-Eulerian perspective coupling solution, can realistically simulate the bidirectional coupling between solids of different materials and complex fluids, significantly improving the physical realism and visual fidelity of the simulation scene.
Owner:EAST CHINA NORMAL UNIV

Viscoelastic fluid heat flow coupling simulation method for micro-channel structure

A viscoelastic fluid heat flow coupling simulation method oriented to a micro-channel structure comprises the steps that pretreatment is conducted, and a viscoelastic fluid constitutive model and material attributes are defined; then constructing a viscoelastic fluid heat flow coupling simplified mathematical model comprising a continuity equation, a simplified momentum equation, a simplified energy equation and a viscoelastic fluid constitutive equation based on logarithm reconstruction, and finally performing finite element simulation verification on the simplified mathematical model; according to the method, a mathematical model is simplified, a physical mechanism necessary for describing the flow and heat transfer coupling phenomenon of the low-Reynolds-number viscoelastic fluid in the micro-channel is reserved, and the numerical solution difficulty and the calculation cost of the model are reduced while the calculation precision is ensured; the method is suitable for efficiently and stably simulating the steady-state heat flow distribution of the viscoelastic fluid in the micro-channel device under the Reynolds number, and a new thought is provided for design and optimization of applications such as micro-channel heat management and micro-channel chips.
Owner:XI AN JIAOTONG UNIV

A ship trajectory identification method and system based on VTS radar

This invention discloses a ship trajectory recognition method and system based on VTS radar, belonging to the field of ship traffic monitoring technology. The method includes constructing a continuity equation, marking divergence anomaly regions, generating a preliminary trajectory point set, extracting the complex signal from the preliminary trajectory point set, setting a dynamic threshold, and marking a set of core points with high interaction. Starting from each core point, the method tracks the trajectory along the dominant direction, sets a direction offset threshold, forms a trajectory set, constructs an Eulerian grid based on the trajectory set, marks non-physical trajectory segments, corrects the non-physical trajectory segments, and generates a trajectory point set. This invention improves the accuracy and robustness of target trajectory recognition by mapping complex signals to an energy density field and combining it with energy flow vector field analysis. It also improves the accuracy of target trajectory tracking by combining changes in energy flow with trajectory adjustment, and avoids retaining unreasonable trajectory segments through Eulerian grid time consistency analysis and trajectory correction.
Owner:YANTAI SANHANG RADAR SERVICE TECH INSITITUTE

Method for calculating critical submerged water depth of side water inlet based on CSSS method

The invention discloses a method for calculating the critical submerged water depth of a side water inlet based on a CSSS method. According to the method, a point sink spherical critical plane model is constructed, and a conservation relation between an effective working area and a radial flow velocity is established based on a continuity equation. For a complex boundary working condition, a dimensionless criterion is introduced to judge the effectiveness of a spherical hypothesis, anisotropic ellipsoid correction is started during failure, and a coordinate stretching equivalent method is utilized to calculate a limited effective area. A potential flow geometric component and a dynamic loss component are adopted to construct a physical correction coefficient, and pure statistical regression is replaced. And calculating a dynamic safety margin in combination with a vortex evolution time scale. According to the method, the problem of critical water depth prediction distortion in a complex flow field is solved, and the physical precision and operation safety of engineering design are improved.
Owner:NANJING HYDRAULIC RES INST

Quantitative analysis method and system for diffusion effect of water-rich soft rock splitting permeation and collaborative grouting

This invention relates to the field of geological engineering, specifically to a method and system for quantitatively analyzing the diffusion effect of synergistic grouting in water-rich soft rock fracturing and seepage. The method includes: conducting parameter tests and obtaining time-varying characteristic parameters through orthogonal experiments; establishing a coupled dynamic model including the grout volumetric flow rate equation, seepage motion equation, and flow continuity equation to obtain the spatiotemporal distribution of the grout field, the flow distribution coefficient of the dual-domain coupling, and the grouting parameters at different grouting times; constructing an index system with synergistic effects and obtaining quantitative values ​​of the diffusion effect. This invention constructs a dual-domain coupled dynamic model that couples the grout volumetric flow rate equation, seepage motion equation, flow continuity equation, and stress continuity equation, modifies the classical flow law to adapt to the grout yield stress characteristics, and achieves transient analysis through finite element numerical solution. It can output the spatiotemporal distribution of the grout field, the flow distribution coefficient, and the grouting parameters, and determine the micro-zone division boundary threshold based on experimental data.
Owner:HEFEI UNIV

Water hammer oscillation blocking removal method based on disturbance equation modeling

The invention discloses a water hammer oscillation blockage removal method based on disturbance equation modeling, and relates to the technical field of oil and gas field exploitation and shaft physical blockage removal. Constructing boundary conditions of the negative pulse return-to-zero type switching valve; constructing a disturbance continuity equation and a disturbance momentum equation; the gravity influence is eliminated, and a water hammer wave disturbance equation set is built in combination with the pipeline friction coefficient; according to the interval and the time step length when the target shaft is dispersed, on the basis of the boundary condition of the negative pulse return-to-zero type switching valve, finite difference discrete processing is conducted on the water hammer wave disturbance equation set, and water hammer wave transient control equation sets corresponding to all depth nodes are obtained and solved in parallel; and pressure distribution and speed distribution of the water hammer waves in the propagation process in the target shaft are obtained, and then parameters of water hammer oscillation unblocking operation of the target shaft are designed or adjusted. According to the method, the water hammer wave disturbance equations suitable for different well types are constructed, the gravity effect requirement is eliminated, well depth and channel friction factors are uniformly incorporated into a modeling framework, and high-precision description of the transient propagation process of the water hammer waves is achieved.
Owner:DONGYING CHANGYING PETROLEUM TECH CO LTD