KR102436664B1 - Apparatus, method and computer program for weakly compressible smoothed particle hydrodynamics based fluid analysis simulation - Google Patents

Abstract

A fluid analysis simulation device based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics) includes a modeling unit for modeling a simulation region including a plurality of fluid particles for a fluid, and at least one dummy particle required for fluid analysis simulation for the simulation region. The flow data of a plurality of fluid particles is calculated using a dummy particle arrangement unit that is generated and placed outside the simulation area and at least one dummy particle disposed outside the simulation area, and based on the calculation result, a flow data calculation unit for performing a fluid analysis simulation, wherein in the first step of calculating the flow data, the flow data calculation unit does not include the relative velocity between the dummy particle and the dummy particle and an adjacent fluid particle. based on the dummy particle density.

Description

WCSPH-based fluid analysis simulation device, method and computer program {APPARATUS, METHOD AND COMPUTER PROGRAM FOR WEAKLY COMPRESSIBLE SMOOTHED PARTICLE HYDRODYNAMICS BASED FLUID ANALYSIS SIMULATION}

It relates to a fluid analysis simulation apparatus, method, and computer program based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics).

Computational Fluid Dynamics (CFD) is a field of fluid mechanics that calculates the dynamic motion of a fluid using a computer in a numerical way. Computational fluid dynamics is a partial differential equation, Naiver-Stokes Equation (FDM) (Finite Difference Method), FEM (Finite Element Method), FVM (Finite Volume Method) and SPH (Smoothed Particle Hydrodynamics) methods such as Calculate the flow of the fluid by discretizing it through

There are two methods for calculating the Navier-Stokes equation: a grid-based method for discretizing a spatial domain into a small mesh or grid, and a particle-based method for expressing a fluid as a set of multiple particles.

In the particle-based method, more natural simulations of natural or physical phenomena are possible by expressing the analysis target as particles instead of using a grid. Particle-based methods include Smoothed Particle Hydrodynamics (SPH), Moving Particle Semi-implicit (MPS), and Lattice Boltzmann Method (LBM).

In fluid analysis based on smoothed particle hydrodynamics (SPH), which is one of the particle-based methods, unlike the grid-based method, the step of generating a grid is omitted, so the results of the analysis can be simulated relatively quickly.

In addition, since the SPH-based fluid analysis uses particles without generating a lattice, analysis of free surfaces such as liquid-gas interfaces can be performed relatively easily.

In addition, the SPH-based fluid analysis can perform relatively accurate analysis of multiphase flows including two or more of gas, liquid, and solid.

The particle-based method searches for a plurality of adjacent particles within a certain radius from one particle in order to calculate the flow of a plurality of particles representing a fluid, and calculates flow data with the adjacent particles. In this case, since there are no particles located near the boundary of the simulation region outside the boundary, the number of adjacent particles is insufficient, which causes a problem in calculating the flow data. To solve this problem, dummy particles, which are virtual particles, are placed outside the simulation region, and the flow of particles located near the boundary of the simulation region is calculated using the dummy particles.

Fluid analysis based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics) assumes that the fluid is weakly compressible. WCSPH calculates the density change amount of the reference particle first using the searched adjacent particles, and then calculates the particle pressure using the calculated density. In addition, WCSPH calculates the acceleration, velocity, and position of particles based on the time integral for the calculated density and pressure. Time integration may be applied for every set analysis time interval dt, and the set analysis time interval dt here may be referred to as one step.

However, in the conventional WCSPH-based fluid analysis, in the first step, the fluid particles located near the boundary of the simulation area are suspended due to the influence of the fluid particles and the adjacent dummy particles. There was a problem that an error occurred.

Prior art document: Japanese Patent Registration No. 6009075

The present invention is to solve the above-described problems, by modeling a simulation region including a plurality of fluid particles for a fluid, and generating at least one dummy particle necessary for a fluid analysis simulation for the simulation region to be outside the simulation region. In the first step of calculating the flow data of a plurality of fluid particles using at least one dummy particle disposed outside, performing a fluid analysis simulation for the simulation area based on the calculation results, and calculating the flow data An object of the present invention is to provide an apparatus, method, and computer program for deriving the density of dummy particles based on a series equation that does not include dummy particles and the relative velocities between the dummy particles and adjacent fluid particles.

However, the technical problems to be achieved by the present embodiment are not limited to the technical problems described above, and other technical problems may exist.

As a technical means for achieving the above-described technical problem, an embodiment of the present invention is a fluid analysis simulation apparatus based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics), a simulation area including a plurality of fluid particles for a fluid. A modeling unit for modeling, a dummy particle arrangement unit for generating at least one dummy particle required for fluid analysis simulation for the simulation area and disposing it outside the simulation area, and at least one dummy particle disposed outside the simulation area and a flow data calculation unit that calculates flow data of fluid particles of The density of the dummy particle may be derived based on a series equation that does not include the dummy particle and the relative velocity between the dummy particle and the adjacent fluid particle.

In an embodiment, the flow data calculator may derive the density of the plurality of fluid particles based on a first continuity equation including the relative velocity between the plurality of fluid particles and adjacent dummy particles in the first step have.

In an embodiment, the flow data calculator derives the density of the plurality of fluid particles based on the first continuity equation in steps after the first step, and between the dummy particles and the dummy particles and adjacent fluid particles The density of the dummy particles may be derived based on the second continuity equation including the relative velocity of .

In an embodiment, the flow data calculator may calculate the flow data by approximating the first continuity equation with a kernel function.

In an embodiment, the flow data calculator may derive pressures, accelerations, velocities, and positions of the plurality of fluid particles based on the densities of the plurality of fluid particles.

In an embodiment, in a step after the initial step, the plurality of fluid particles may not float in the vicinity of the dummy particle.

In an embodiment, in the first step, the density of the dummy particles may have the same value as the reference density of the fluid.

In another embodiment of the present invention, in a fluid analysis simulation method based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics), modeling a simulation region including a plurality of fluid particles for a fluid, fluid analysis simulation for the simulation region generating at least one dummy particle necessary for and performing a fluid analysis simulation for the simulation region, wherein the calculating of the flow data includes, in the first step of calculating the flow data, the relationship between the dummy particle and the dummy particle and an adjacent fluid particle. and deriving the density of the dummy particles based on a series equation that does not include velocity.

Another embodiment of the present invention is a computer program stored in a computer readable recording medium including a sequence of instructions for performing a fluid analysis simulation based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics), wherein the computer program is When executed by the method, a simulation region including a plurality of fluid particles for a fluid is modeled, and at least one dummy particle necessary for a fluid analysis simulation for the simulation region is generated and placed outside the simulation region, and the A sequence of instructions for calculating flow data of a plurality of fluid particles using at least one arranged dummy particle, and performing a fluid analysis simulation for the simulation region based on the calculation result, wherein the flow data In an initial step of calculating, the method may further include a sequence of instructions for deriving the density of the dummy particle based on a series equation that does not include the dummy particle and the relative velocity between the dummy particle and an adjacent fluid particle.

The above-described problem solving means are merely exemplary, and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, there may be additional embodiments described in the drawings and detailed description.

According to any one of the above-described problem solving means of the present invention, a simulation region including a plurality of fluid particles for a fluid is modeled, and at least one dummy particle required for a fluid analysis simulation for the simulation region is generated, and the simulation region is It is disposed outside, calculates flow data of a plurality of fluid particles using at least one dummy particle disposed outside, performs fluid analysis simulation on the simulation area based on the calculation results, and calculates flow data. In the step, it is possible to provide a fluid analysis simulation apparatus, method, and computer program for deriving the density of the dummy particle based on a series equation that does not include the dummy particle and the relative velocity between the dummy particle and the adjacent fluid particle.

In addition, by reducing the error of the flow data generated by the dummy particles, the accuracy of the fluid analysis simulation can be improved.

In addition, by effectively predicting the movement of a fluid, it can be applied to various technical fields.

1 is a view for explaining the problems of the conventional fluid analysis simulation method.
2 is a block diagram of a fluid analysis simulation apparatus according to an embodiment of the present invention.
3 is a view for explaining a fluid analysis simulation method according to an embodiment of the present invention.
4 is an exemplary view comparing the fluid analysis simulation results to which the fluid analysis simulation method according to the prior art and the fluid analysis simulation method according to an embodiment of the present invention is applied.
5 is an exemplary view comparing the fluid analysis simulation results to which the fluid analysis simulation method according to the prior art and the fluid analysis simulation method according to an embodiment of the present invention is applied.
6 is a flowchart of a fluid analysis simulation method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is "connected" with another part, this includes not only the case of being "directly connected" but also the case of being "electrically connected" with another element interposed therebetween. . Also, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated, and one or more other features However, it is to be understood that the existence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded in advance.

In this specification, a "part" includes a unit realized by hardware, a unit realized by software, and a unit realized using both. In addition, one unit may be implemented using two or more hardware, and two or more units may be implemented by one hardware. Meanwhile, '~ unit' is not limited to software or hardware, and '~ unit' may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card.

Some of the operations or functions described as being performed by the terminal or device in this specification may be instead performed by a server connected to the terminal or device. Similarly, some of the operations or functions described as being performed by the server may also be performed in a terminal or device connected to the corresponding server.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining the problems of the conventional fluid analysis simulation method.

Referring to FIG. 1A , fluid particles 10 positioned inside the simulation region and dummy particles 20 positioned outside the simulation region are shown, and arrows indicate the flow direction of the fluid.

According to the conventional WCSPH-based fluid analysis, the dummy particle 20 of the portion 101 where the fluid particle 10 and the dummy particle 20 are first adjacent to each other as the fluid particle 10 proceeds in the traveling direction after the initial step. As the density of the fluid particles 10 increased, a phenomenon occurred in which the fluid particles 10 were suspended. As a result, as shown in (b) of FIG. 1 , the fluid particles 10 float and the accuracy of the calculation of the flow data is deteriorated. Here, the first step means the time from the start of the fluid analysis simulation to the corresponding time interval when the fluid analysis simulation is performed after the user sets the analysis time interval dt in the fluid analysis simulation device.

This is because, when calculating the density in WCSPH, the density of the dummy particle 20 is abnormally high immediately after the first step by calculating the density change amount based on the value of the relative velocity between the dummy particle 20 and the fluid particle 10. .

Specifically, at the same time as starting the analysis of the flow, as the stationary fluid particle 10 starts to move, the relative velocity between the dummy particle 20 and the fluid particle 10 increases instantaneously, thereby increasing the density change and The density value protrudes larger than the actual value. Also, due to an error in the density of the dummy particle 20 in the portion 101 where the fluid particle 10 and the dummy particle 20 are initially adjacent to each other, an error also occurs in the density of the dummy particle 20 derived later. will do

That is, since the density of the dummy particles 20 in the portion 101 where the fluid particles 10 and the dummy particles 20 are initially adjacent to each other is inaccurately derived, an error occurs in the calculation of the flow data in all steps. Therefore, in the first step, the value of the density of the dummy particles 20 has a great influence on the accuracy of the overall flow analysis simulation result.

2 is a block diagram of a fluid analysis simulation apparatus according to an embodiment of the present invention. Referring to FIG. 2 , the fluid analysis simulation apparatus 200 may include a modeling unit 210 , a dummy particle arrangement unit 220 , and a flow data calculation unit 230 .

The fluid analysis simulation apparatus 200 may include a server, a desktop, a laptop computer, a kiosk (KIOSK) and a smartphone, and a tablet PC. However, the fluid analysis simulation apparatus 200 is not limited to those exemplified above. That is, the fluid analysis and simulation apparatus 200 may include all devices equipped with a processor for performing a WCSPH-based fluid analysis and simulation method to be described later.

The fluid analysis simulation apparatus 200 performs a three-dimensional flow analysis of the fluid. That is, the fluid analysis simulation apparatus 200 models the three-dimensional simulation region and the plurality of particles positioned in the three-dimensional simulation region, and analyzes the flow of the plurality of particles in the three-dimensional simulation region.

The fluid analysis simulation apparatus 200 may perform a simulation for analyzing a fluid based on smoothed particle hydrodynamics (SPH). SPH (Smoothed Particle Hydrodynamics) is one of the particle-type fluid analysis techniques that can be used in Computational Fluid Dynamics (CFD). In order to simulate the movement of a fluid, SPH may express a fluid to be analyzed as one or more particles. The SPH can calculate the physical quantity of each particle while tracking each particle, and perform a fluid analysis simulation based on the calculation result.

The fluid analysis simulation method according to the present invention includes, but is not limited to, an application field in which a fluid analysis simulation is calculated in real time, and is applied to various application fields requiring fluid analysis simulation. Exemplary applications include, for example, computer games, medical simulations, scientific applications, and computer animation.

The modeling unit 210 may model a simulation region including a plurality of particles for a fluid. For example, the modeling unit 210 receives at least one of terrain information, structure information, boundary condition information, particle property information, and gravitational acceleration information from a user using a keyboard, mouse, joystick, touch screen, and microphone, The simulation region may be modeled based on at least one input.

Here, the structure information may include at least one of a density, a coefficient of restitution, and a coefficient of friction.

In addition, the particle property information may include at least one of a particle radius, a density, a viscosity, a speed of sound, and an initial velocity.

The dummy particle arrangement unit 220 may generate at least one dummy particle required for fluid analysis simulation for the simulation area and arrange it outside the simulation area. For example, the dummy particle arranging unit 220 may generate a plurality of basic dummy particles to be disposed outside the simulation region, and may place the generated at least one basic dummy particle in the simulation region.

The flow data calculator 230 may determine a reference particle that is a calculation target of flow data among a plurality of particles for the fluid, and search for a plurality of adjacent particles located within a predetermined search radius from the determined reference particle. The flow data calculator 230 may calculate flow data of a plurality of particles using at least one dummy particle disposed outside.

The flow data calculation unit 230 calculates flow data generated due to a collision between each particle and an adjacent particle or a collision between each particle and a polygon constituting the structure model, and based on the calculation result, a fluid analysis simulation for the simulation area can be performed.

In the first step of calculating the flow data, the flow data calculator 230 may derive the density of the dummy particles based on a series equation that does not include the relative velocity between the dummy particles and the dummy particles and the adjacent fluid particles. The flow data calculator 130 may derive the density of the dummy particles in the first step based on Equation 1, for example. Here, i may be a reference particle, j is an adjacent particle within a certain radius, ρ is a density, and m is a mass.

In the case of using Equation 1, the density of the dummy particles in the first step may be equal to or lower than the density of the fluid particles. Also, in steps after the first step, the density of the dummy particles may not have an abnormally high value.

That is, in the case of using Equation 1, since the density of the dummy particle is derived without considering the relative velocity between the dummy particle and the dummy particle and the adjacent fluid particle in the first step, the density of the conventional dummy particle is derived as an abnormally large value. no problems arise Further, since the fluid particles do not float immediately after the first step, the fluid particles do not float near the dummy particles even in the steps after the first step.

In the first step, the flow data calculator 230 may derive the density of the plurality of fluid particles based on a first continuity equation including the relative velocity between the plurality of fluid particles and the adjacent dummy particles. The flow data calculator 230 may calculate the flow data by, for example, approximating the first continuity equation with a kernel function.

The flow data calculator 130 may derive the density of the fluid particles in the first step based on Equation 2, for example. Here, i is a reference particle, j is an adjacent particle within a certain radius, ρ is a density, m is a mass, and u may be a velocity.

The flow data calculator 230 may derive the density of the plurality of fluid particles based on the first continuity equation in steps after the initial step. The flow data calculator 230 may derive the density of a plurality of fluid particles in steps after the initial step based on Equation 2 described above, for example.

The flow data calculator 230 may derive the density of the dummy particles based on a second continuity equation including the dummy particles and the relative velocity between the dummy particles and the adjacent fluid particles in steps after the first step. The flow data calculator 230 may derive the density of dummy particles in steps after the initial step based on Equation 2 described above, for example.

The flow data calculator 230 may derive pressures, accelerations, velocities, and positions of the plurality of fluid particles based on the densities of the plurality of fluid particles.

는 음속이고,

는 비열비이고,

는 기준 밀도(처음에 설정한 유체의 밀도)일 수 있다.WCSPH assumes the fluid is weakly compressible and analyzes the flow. The flow data calculator 230 may derive the pressure of the fluid particles based on Equation 3, for example. where P is the pressure, ρ is the density,

is the speed of sound,

is the specific heat ratio,

may be a reference density (density of the fluid initially set).

는 속도이고,

는 점성이고,

는 중력가속도이고,

는 압력일 수 있다.The flow data calculator 230 may derive the acceleration of the fluid particle based on Equation 4, for example. here,

is the speed,

is the viscosity,

is the gravitational acceleration,

may be pressure.

The flow data calculation unit 230 calculates change values of flow data such as density, pressure, and viscosity of each particle by using the WCSPH algorithm. For example, the flow data calculator 230 calculates the flow data of each particle in the next time step (first time step) based on the initial flow data of each particle, and calculates the flow of each particle based on this. do.

In addition, the flow data calculator 230 calculates the flow data of each particle in the next time step based on the flow data of each particle in the first time step, and calculates the flow of each particle based on this.

The flow data calculator 230 calculates the flow data of each particle at each time step and calculates the flow of each particle, thereby performing the fluid analysis simulation.

Returning to FIG. 2 , the flow data calculator 230 may perform a fluid analysis simulation on the simulation area based on the calculation result.

Referring to FIG. 3A , fluid particles 10 positioned inside the simulation region and dummy particles 20 positioned outside the simulation region are shown, and arrows indicate the flow direction of the fluid.

According to the fluid analysis simulation method according to an embodiment of the present invention, as the fluid particle 10 proceeds, the fluid particle 10 and the dummy particle 20 are first adjacent to each other. density does not increase. Therefore, as shown in (b) of FIG. 3 , the fluid particle 10 proceeds without abnormally floating in the vicinity of the portion 301 where the fluid particle 10 and the dummy particle 20 first adjoin. can be checked

4 and 5 are exemplary views comparing fluid analysis simulation results to which the fluid analysis simulation method according to the prior art and an embodiment of the present invention is applied.

4 is a comparison of fluid analysis simulation results of a Dam-break case (Kleefsman). Fig. 4 (a) exemplarily shows a fluid analysis simulation result to which a conventional WCSPH-based method is applied. Referring to FIG. 4A , it can be seen that the fluid particles move while floating at the boundary of the simulation region.

FIG. 4 (b) exemplarily shows a fluid analysis simulation result to which the method according to an embodiment of the present invention is applied. Compared with FIG. 4 (a), fluid particles floating at the boundary of the simulation area are It can be seen that there is a marked decrease.

4 (c) and (d) are views comparing a pressure value and an experimental value (measured value) among the calculation results of flow data according to the prior art and an embodiment of the present invention, compared to the prior art, the method of the present invention In the case of , it was found that the occurrence of noise was reduced in the calculation results of the flow data and the degree of agreement with the experimental value was increased. In addition, it was found that the negative pressure phenomenon occurring in the prior art does not occur.

5 is a comparison of fluid analysis simulation results of the sloshing case (M.Peric). The sloshing case is known as the most basic verification case in the shipbuilding and offshore field.

Fig. 5 (a) exemplarily shows a fluid analysis simulation result to which a conventional WCSPH-based method is applied. Referring to (a) of FIG. 5 , fluid particles move while floating at the boundary portion of the simulation region, and the pressure at the boundary portion becomes unstable.

FIG. 5 (b) is an exemplary view showing a fluid analysis simulation result to which the method according to an embodiment of the present invention is applied, and compared with FIG. 5 (a), fluid particles floating at the boundary of the simulation area are It can be seen that the decrease is clearly reduced, and the pressure at the boundary is stably shown.

Figure 5 (c) is a view comparing the pressure value and the experimental value (measured value) among the calculation results of flow data according to the prior art and an embodiment of the present invention, in the case of the method of the present invention compared to the prior art In the calculation results of the flow data, it was found that the occurrence of noise was reduced, the degree of agreement with the experimental value increased, and the pressure value was calculated more stably. In addition, it can be confirmed that a secondary peak that did not appear in the prior art also occurs.

6 is a flowchart of a fluid analysis simulation method according to an embodiment of the present invention. The fluid analysis simulation method 600 shown in FIG. 6 includes steps processed in time series by the fluid analysis simulation apparatus 200 according to the embodiment shown in FIG. 2 . Therefore, even if omitted below, it is also applied to the method of performing the fluid analysis simulation performed in the fluid analysis and simulation apparatus 200 according to the embodiment shown in FIG. 2 .

In operation S610, the fluid analysis simulation apparatus 200 may model a simulation region including a plurality of fluid particles for a fluid.

In operation S620 , the fluid analysis and simulation apparatus 200 may generate at least one dummy particle required for fluid analysis simulation for the simulation region and arrange it outside the simulation region.

In operation S630 , the fluid analysis and simulation apparatus 200 may calculate flow data of a plurality of fluid particles using at least one dummy particle disposed outside.

In operation S640, the fluid analysis simulation apparatus 200 may perform a fluid analysis simulation on the simulation area based on the calculation result.

In the above description, steps S610 to S640 may be further divided into additional steps or combined into fewer steps, according to an embodiment of the present invention. In addition, some steps may be omitted as necessary, and the order between the steps may be switched.

The method of performing fluid analysis simulation in the fluid analysis simulation apparatus described with reference to FIG. 6 may be implemented in the form of a computer program stored in a medium executed by a computer or a recording medium including instructions executable by the computer. In addition, the method of performing fluid analysis simulation in the fluid analysis simulation apparatus described with reference to FIG. 6 may be implemented in the form of a computer program stored in a medium executed by a computer.

Computer-readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. Also, computer-readable media may include computer storage media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data.

The foregoing description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and likewise components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

200: fluid analysis simulation device
210: modeling unit
220: dummy particle arrangement unit
230: floating data calculation unit

Claims (15)

In a fluid analysis simulation device based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics),
a modeling unit for modeling a simulation region including a plurality of fluid particles for a fluid;
a dummy particle arrangement unit for generating at least one dummy particle necessary for fluid analysis simulation of the simulation area and disposing it outside the simulation area;
A flow data calculation unit that calculates flow data of a plurality of fluid particles using the at least one dummy particle disposed outside, and performs a fluid analysis simulation on the simulation area based on the calculation results
including,
In the first step of calculating the flow data, the flow data calculator derives the density of the dummy particles based on a series equation that does not include the relative velocity between the dummy particles and the dummy particles and adjacent fluid particles, and deriving the density of the plurality of fluid particles based on a first continuity equation including the relative velocities between the plurality of fluid particles and adjacent dummy particles.
delete The method of claim 1,
The flow data calculation unit derives the density of the plurality of fluid particles based on the first continuity equation in steps after the first step, and includes the dummy particles and the relative velocities between the dummy particles and adjacent fluid particles. The fluid analysis simulation apparatus to derive the density of the dummy particles based on the second continuity equation.
The method of claim 1,
Wherein the flow data calculator calculates the flow data by approximating the first continuity equation with a kernel function, the fluid analysis simulation apparatus.
5. The method of claim 4,
The flow data calculation unit will derive the pressure, acceleration, velocity, and position of the plurality of fluid particles based on the density of the plurality of fluid particles, a fluid analysis simulation device.
The method of claim 1,
In steps after the first step, the plurality of fluid particles do not float in the vicinity of the dummy particles.
The method of claim 1,
In the first step, the density of the dummy particles will have the same value as the reference density of the fluid, fluid analysis simulation apparatus.
In the fluid analysis simulation method based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics) performed in the fluid analysis simulation device,
modeling a simulation region comprising a plurality of fluid particles for a fluid;
generating at least one dummy particle necessary for fluid analysis simulation for the simulation area and disposing it outside the simulation area;
calculating flow data of a plurality of fluid particles using the at least one dummy particle disposed outside; and
performing a fluid analysis simulation on the simulation area based on the calculation result
including,
In the first step of calculating the flow data, the calculating of the flow data may include deriving the density of the dummy particles based on a series equation that does not include the relative velocities between the dummy particles and the dummy particles and adjacent fluid particles. to do; and
In the first step, the fluid analysis simulation method comprising the step of deriving the density of the plurality of fluid particles based on a first continuity equation including the relative velocities between the plurality of fluid particles and adjacent dummy particles .
delete 9. The method of claim 8,
The step of calculating the flow data is a step after the first step,
deriving the density of the plurality of fluid particles based on the first continuity equation; and
deriving the density of the dummy particles based on a second continuity equation comprising the dummy particles and the relative velocities between the dummy particles and adjacent fluid particles;
Which will further include, the fluid analysis simulation method.
9. The method of claim 8,
The calculating of the flow data may include calculating the flow data by approximating the first continuous equation with a kernel function.
12. The method of claim 11,
wherein calculating the flow data comprises deriving pressures, accelerations, velocities and positions of the plurality of fluid particles based on the densities of the plurality of fluid particles.
9. The method of claim 8,
In steps after the first step, the plurality of fluid particles do not float in the vicinity of the dummy particles, the fluid analysis simulation method.
9. The method of claim 8,
In the first step, the density of the dummy particles will have the same value as the reference density of the fluid, fluid analysis simulation method.
In a computer program stored in a computer-readable recording medium including a sequence of instructions for performing a fluid analysis simulation based on WCSPH (Weakly Compressible Smoothed Particle Hydrodynamics),
When the computer program is executed by a computing device,
modeling a simulation region comprising a plurality of fluid particles for a fluid;
At least one dummy particle required for fluid analysis simulation for the simulation area is generated and placed outside the simulation area;
calculating flow data of a plurality of fluid particles using at least one dummy particle disposed outside,
and a sequence of instructions to perform a fluid analysis simulation for the simulation area based on the calculation result,
In the first step of calculating the flow data, the density of the dummy particles is derived based on a series equation that does not include the relative velocities between the dummy particles and the dummy particles and adjacent fluid particles, the plurality of fluid particles and and a sequence of instructions for deriving a density of the plurality of fluid particles based on a first continuity equation comprising relative velocities between adjacent dummy particles.

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