CN116595745A - High-precision capturing method for high-impact material interface based on particle level set - Google Patents

Abstract

The application discloses a high-precision capturing method of a strong impact material interface based on a particle Level Set, and relates to the field of multiphase flow numerical simulation. According to the method, whether the distance indication function value at the grid point needs to be updated or not is judged through a projection method, interference caused by particle correction is reduced, and a high-precision strong impact material interface can be captured. And the calculation time consumption of the solving method is less, the efficiency of interface capturing is improved, and the consumption of calculation resources is reduced.

Description

High-precision capturing method for high-impact material interface based on particle level set

Technical Field

The application relates to the field of multiphase flow numerical simulation, in particular to a high-precision capturing method of a high-impact material interface based on a particle level set.

Background

The capture and handling of material interfaces is a central problem in multiphase flow numerical simulation, especially for compressible multiphase fluids under high impact extreme conditions such as underwater explosions, where the interfaces can undergo rather complex topological changes such as crushing, coalescence, inversion, etc., which greatly increases the difficulty of numerical simulation. The current material interface description methods can be classified into lagrangian and euler methods. The Lagrangian method directly tracks the motion of fluid particles, can accurately track the interface change, processes discontinuous non-numerical dissipation, but is difficult to process complex interface shape change, has relatively low calculation efficiency, and simultaneously has the problems of unstable tension, particle aggregation and the like. The Euler method can easily process the change of the topological structure of a complex interface by constructing a transport equation of an additional variable to reconstruct or directly capture the position and the shape of the interface, has higher calculation efficiency, and is widely applied to interface description. Therefore, the Euler method is very suitable for simulating the strong impact compressible multiphase fluid such as underwater explosion.

Under the framework of Euler description methods, there are two main types of simulation methods: 1) The material interface is considered as a diffusion band of finite thickness, primarily introducing a mixed model description interface, such as a gamma-model, but such simulation methods can result in non-physical mixing or spurious pressure oscillations. (2) The material interface is considered as a clear interface of zero thickness, and the most representative of such simulation methods are the Volume of Fluid (VOF) method and the Level-Set (LS) method. The VOF method reconstructs interfaces according to the volume fraction values of different grid units in the flow field, has good conservation, but has low overall precision, is difficult to accurately obtain the positions of the interfaces, and is difficult to popularize in high-order precision and three-dimensional conditions. The LS method defines a directional distance function from the interface in the flow field, and obtains the motion state of the interface by solving the transport equation of the distance function. The method can obtain a smooth interface and accurate interface parameters such as an interface normal line, curvature and the like, but has the obvious problem of quality loss in the process of reinitialization, and seriously influences the effect of interface capture.

In contrast, the LS method has a prominent interface capture advantage, while the key problem is to solve the mass loss, and three different solutions are currently mainly available. The first is to improve the re-initialization process to reduce the quality loss, which is not sufficiently obvious in optimization. The second is to couple the LS method with other euler methods, such as CLSVOF method, which improves both curvature calculation and mass loss of the VOF method, but is currently mainly applied to incompressible fluids, which has limitations and high computational complexity. The third method is to combine the LS method with the lagrangian method, for example, the Particle Level Set (PLS) method, introduce lagrangian particles into the LS method, and correct the interface by using escape particles, which is a high-precision interface capturing method. Compared with other methods, the PLS method has the advantages of obviously improving the interface precision and conservation, and can be used for accurately describing the interface of the severe change of the two-phase flow. However, in practice, the conventional PLS method tends to capture material interfaces with insufficient accuracy.

Disclosure of Invention

Aiming at the problems and the technical requirements, the inventor provides a high-precision capturing method of a high-impact substance interface based on a particle level set, and the technical scheme of the application is as follows:

a high-precision capturing method of a high-impact material interface based on a particle level set comprises the following steps:

grid division is carried out on a flow field calculation domain of the strong-impact compressible multiphase flow to obtain a plurality of grid units;

determining a time step t according to the constructed Level-Set equation ⁰ Strong impact material interface Γ (t) ⁰ ) The passing grid cells are used as interface grids, and particle information of particles in each interface grid is initialized;

at any time step t ⁿ According to time step t ⁿ Particle information of (a) and time step t ⁿ Is attracted to the strong impact material interface Γ (t) ⁿ ) N is a parameter with a start value of 0;

performing first-order dispersion of time dimension by using a semi-Lagrangian method, performing dispersion of space dimension by using the semi-Lagrangian method or a finite volume method, and solving a Level-Set equation and a particle transport equation to obtain a time step t of each grid point of each grid unit ⁿ⁺¹ Distance indication function value of (2) and time step t ⁿ⁺¹ Particle information of (2);

at time step t according to each grid point ⁿ⁺¹ Distance indication function value of (c) and time step t ⁿ⁺¹ Determining escape particles and obtaining projections of the escape particles on grid point normal lines of the grid cells, and correcting the grid points at time step t ⁿ⁺¹ Distance indication function value of (2);

reinitializing the distance indication function value of the flow field calculation domain and obtaining a time step t ⁿ⁺¹ Strong impact material interface Γ (t) ⁿ⁺¹ )；

Let n=n+1 and execute again according to time step t ⁿ Particle information of (a) and time step t ⁿ Is attracted to the strong impact material interface Γ (t) ⁿ ) And the steps are carried out until all time steps are solved, and the capture of the strong impact material interface of the strong impact compressible multiphase flow is completed.

The beneficial technical effects of the application are as follows:

the application discloses a high-precision capturing method of a strong impact material interface based on a particle level set.

In addition, when solving the Level-Set equation, the semi-Lagrangian method is adopted to perform first-order precision dispersion in time and space, so that the method is unconditionally stable, the calculation time is reduced, the consumption of resources is greatly reduced, or the method can be applied to a limited volume method, and compared with the traditional method, the method is higher in applicability and lower in limitation.

The method considers the serious deformation condition of the interface of the strong impact substance, and distributes the added particles according to the curvature condition of the interface of the strong impact substance when the particles are added so as to add the particles in the interface area which is most required to be corrected. The method greatly improves the utilization rate of particles, reduces the consumption of resources and improves the calculation efficiency.

Drawings

FIG. 1 is a flow chart of a method for high precision capture of a high impact material interface in accordance with one embodiment of the present application.

Fig. 2 is a schematic diagram of the relationship between escaping particles and four grid points of a grid cell in which they are located in one embodiment of the application.

FIG. 3 is a schematic representation of a strong impact material interface captured using the method of the present application in an experimental example.

Fig. 4 is a schematic diagram of another high impact material interface captured in the experimental example using the method of the present application.

FIG. 5 is a schematic representation of a strong impact material interface and pressure contour plot captured using the method of the present application in another experimental example.

Detailed Description

The following describes the embodiments of the present application further with reference to the drawings.

The application discloses a high-precision capturing method of a high-impact substance interface based on a particle level set, referring to a flow chart shown in fig. 1, the high-precision capturing method of the high-impact substance interface comprises the following steps:

step S1, grid division is carried out on a flow field calculation domain of the strong-impact compressible multiphase flow to obtain a plurality of grid units.

Step S2, determining a time step t according to the constructed Level-Set equation ⁰ Strong impact material interface Γ (t) ⁰ ) The passing grid cells serve as interface grids, and particle information of particles in each interface grid is initialized.

Since the particle level set is based on the LS method, it is first necessary toTo construct the Level-Set equationX is a position parameter, t ⁿ Is a time parameter and represents an nth time step, n being a parameter with a start value of 0. This is because the LS method regards the material interface as a function of time +.>Zero isosurface of->Satisfying a certain equation. At each time step t ⁿ Only need to find +.>Distance indication function value +.>The time step t can be known ⁿ Strong impact material interface Γ (t) ⁿ ) Is (are) located>Omega denotes the surrounding strong impact material interface Γ (t) ⁿ ) Is a region of (a) in the above-mentioned region(s). The constructed Level-Set equation is:

in the above, the speed

At an initial time step t ⁰ Initialized distance indication function value

wherein ,Ω＝Ω₁ ∪Ω ₂ ，Ω ₁ and Ω₂ Respectively representing the regions on both sides of the interface of the high impact material. d (X, Γ (t) ⁰ ) Represents the point at coordinate X to Γ (t) ⁰ ) At the interface of the high impact material,the area in which a fluid is present is shown,indicating the region where another fluid is located.

Distance indication function value of grid point of grid unit according to constructed Level-Set equationThe interface grid can be determined by calculation: if the distance indication function value of each grid point of one grid unit +.>And determining the grid cell as an interface grid if the signs of the grid cells are different.

At an initial time step t ⁰ The particles were arranged into an interface grid, the particles were laid out along the local coordinates of the interface grid, and 4 particles were arranged in each direction. The particle information of each particle includes the position X of the particle _P Particle at X _P Flow rate atParticle symbol s _P Particle radius r _P Wherein when the distance indication function value of the particle is positive and the particle is positive, the particle sign s _P =1; when the distance indication function value of the particle is negative, the particle sign s is that the particle is negative _P = -1. Particle radius r _P The following settings were made according to the PLS method:

wherein ,r_min ＝0.1Δh，r _max =0.5 Δh, Δh is the minimum value of the grid cell pitch,is position X _P The distance indication function value of the particle at the position can be obtained by interpolation according to the distance indication function value of the grid point. Different particles may overlap each other.

Step 3, at any time step t ⁿ According to time step t ⁿ Particle information of (a) and time step t ⁿ Is attracted to the strong impact material interface Γ (t) ⁿ ) And (3) upper part.

After initialization, the particles are attracted to the strong impact material interface along the shortest path, and the positions of the attracted particles are updated as follows because the shortest path is along the normal direction of the material interface:

wherein ,X_new Is position X _P Where the updated position of the particle, λ is the attraction coefficient and λ=1,is an ideal Level-Set function value of 0 (indicating that the particle is ultimately directed onto the interface), n (X _P ) Is position X _P Normal to the axis. By attracting particles several iterations and deleting particles that are not attracted to the high impact material interface, the particles attracted to the high impact material interface will subsequently migrate with the flow and update position.

Step 4, solving a Level-Set equation and a particle transport equation to obtain the time step t of each grid point of each grid unit ⁿ⁺¹ Distance indication function value of (2) and time step t ⁿ⁺¹ Particle information of (a).

(1) In a method, performing first-order dispersion of a time dimension by using a semi-Lagrangian method, performing first-order dispersion of a space dimension by using the semi-Lagrangian method, comprising:

performing first-order dispersion of space dimension on a flow field calculation domain, and determining coordinates G of grid points of an ith row and a jth column _i,j = (iΔx, jΔy), and coordinate G _i,j Speed atΔx is the unit step in the row direction, Δy is the unit step in the column direction, u _i,j Is the velocity in the row direction, v _i,j Is the velocity along the column direction, i and j are parameters.

Performing first-order dispersion of time dimension on the time step, and determining any time step t ⁿ =n·Δt, Δt being the unit step of the time dimension.

Solving the Level-Set equation according to the semi-Lagrangian method to obtain a coordinate G _i,j At time step t ⁿ⁺¹ The distance indication function value of (2) is:

wherein ,representing the coordinates G _r+1,s+1 At time step t ⁿ Distance indication function value,/->Representing the coordinates G _r,s+1 At time step t ⁿ Distance indication function value,/->Representing the coordinates G _r+1,s At time step t ⁿ Distance indication function value,/->Representing the coordinates G _r,s At time step t ⁿ Distance indication function value of (2);

the velocity of each particle can be determined by interpolation of the velocity of each grid pointThen solve the particle transport equation +.>Particle positions of the particles after the particles are updated with the flow can be determined. The particle sign s after the update of the particles along with the flow can be obtained by interpolating the distance indication function value of each grid point _P Particle radius r _P Thereby obtaining an updated time step t ⁿ⁺¹ Particle information of (a).

The method is unconditionally stable, so that the size of the time step is not controlled by the CFL condition based on stability, which is helpful for reducing the time overhead of calculation and improving the calculation efficiency.

(2) In another method, the first-order dispersion of the time dimension is performed by using a semi-Lagrangian method, and the dispersion of the space dimension is performed by using a finite volume method, including:

the constructed Level-Set equation isThe gradient of the Level-Set equation based on the finite volume method to obtain the spatial discretization is +.>The semi-discrete form of the Level-Set equation is obtained as

wherein ,A_f Is the area of the calculation unit surface, V _cell To calculate the volume of the cell, n _f To calculate the unit external normal of the cell surface, ρ is the medium density, u is the flow velocity,is a distance indication function value and faces is a set of computational element planes.

The remaining time-discrete method and the subsequent solving method are similar to the first method, and the embodiment will not be described again.

Step 5, according to each grid point at time step t ⁿ⁺¹ Distance indication function value of (c) and time step t ⁿ⁺¹ Determining escape particles and obtaining projections of the escape particles on grid point normal lines of the grid cells, and correcting the grid points at time step t ⁿ⁺¹ Is indicative of the function value.

The interface correction is a key step for accurately capturing the interface of the strong-impact compressible multiphase fluid, so that the error caused by the numerical dissipation of an LS method can be effectively reduced, and the interface precision is improved. During the calculation, a portion of the particles drift across the high impact material interface, and when the drift exceeds the particle radius, it is called an escape particle. When the particle sign of one escape particle before drifting is positive and the particle sign of one escape particle after drifting is negative, the escape particle is positive escape particle, and when the particle sign of one escape particle before drifting is negative and the particle sign of one escape particle after drifting is positive, the escape particle is negative escape particle.

In the conventional interface correction method, the coordinate X _P Radius r of particle _P Particle symbol s _P The correction value of the escape particle pair of the grid point of the nearby coordinate X isFor each escape positive particle, de-reconstruct +.>Calculates a correction value of grid points of the grid cell containing the escape positive particles +.>For each grid point, there may be multiple escape particles around the grid point, so the distance indication function value of the grid point is compared with the calculated correction value of each escape positive particle>Compare and indicate the distance of the grid point as function value +.>Correction to->The same is true for escape negative particles, and the correction value of each escape negative particle is calculated and obtained>After that, the distance indication function value of the grid point is +.>Correction to->Adopts-> and />The minimum reconstruction interface of (a) is: />

However, when the interface of the high impact material is severely deformed, a part of the regions lack a sufficient number of particles, and a large number of particles are accumulated in some regions, which may lead to inaccurate interface correction when the interface correction is performed according to the conventional method.

As shown in fig. 2, assuming that the particle center of one escape particle is P, the escape particleThe coordinates of the four grid points of the grid unit where the escape particles are located are G respectively _i,j+1 、G _i+1,j+1 、G _i,j and G_i+1,j . According to the conventional interface correction method, the escaping particles correspond to the coordinates G _i,j+1 Correction value of grid point D of (2)The escaping particles have a relative coordinate G _i+1,j Correction value +.>After comparison, the distance indication function value of grid point D is obtained>Correction to->Distance indication function value of grid point A>The original value is maintained. In this scenario, for the escaping particle, the distance from the grid point to the particle center P is |X-X _P I is always larger than the particle radius r of the escape particle _P Thus the coordinate X _P Radius r of particle _P Particle symbol s _P The correction value of the grid point of the coordinate X in the vicinity of the grid point by the escape positive particles is:

coordinate X _P Radius r of particle _P Particle symbol s _P The correction value of the grid point of the coordinates X in the vicinity of the grid point by the escape negative particles of (a) is:

wherein ,is the distance indication function value of the grid point of the coordinate X.

According to the above formula, the determined coordinates G _i,j+1 The corrected distance indication function value of grid point D isCoordinates G _i+1,j Is a distance indication function value of +.>Coordinates G _i+1,j+1 Is a distance indication function value of +.>It was confirmed that this time was not corrected in the above-described manner.

To solve this problem, the present application corrects the escape particles based on their projections onto the grid point normal of the grid cell where they are located. Comprising the following steps: determining each grid point of a grid unit where the escape particles are located, determining an intersection point of a connecting line of the grid point and the particle center of the escape particles on the boundary of the escape particles for any grid point, and calculating coordinates of a projection point of the intersection point on the normal line of the grid point, wherein the obtained coordinates are as follows:

X′＝X+γproj _n (X _P -X)；

wherein ,proj _n (X _P -X) represents (X) _P -X) projection onto the normal n of grid point with coordinates X, ±>Distance indication function value based on grid point with coordinate X>A determined normal.

When the coordinates of the projection point are located in the grid unit where the escape particles are located, the particle information of the escape particles is utilized to correct the grid point at the time step t ⁿ⁺¹ Is indicative of the function value. Comprising the following steps:

when the escaping particles are escaping positive particles, determining that the escaping positive particles are correct values of grid points nearbyAccording to->At time step t for the grid point ⁿ⁺¹ Distance indication function value +.>Correcting;

when the escaping particles are escaping negative particles, determining that the escaping negative particles are correct values of grid points nearbyAnd according to->At time step t for the grid point ⁿ⁺¹ Distance indication function value +.>And (5) performing correction.

For example, in fig. 2, for an escape particle having a particle center P, an intersection point of a line connecting a grid point D and the particle center P of the escape particle on the boundary of the escape particle is determined as C, and a normal n of the intersection point C at the grid point D is calculated _i,j+1 Coordinates of the projected points on the grid cell are determined and located in the grid cell, and then corrected according to the method. For grid point I, the intersection point of the line between grid point I and the particle center P of the escaping particle on the boundary of the escaping particle is E, and the normal n of the intersection point E at grid point I is calculated _i+1,j+1 Coordinates of the projection point H on the map and determining that it is not locatedIn the grid cell, the grid point I is therefore not corrected by the escape particles. By the method, interference caused by particle correction can be reduced, so that more accurate distance indication function values can be captured. By the interface correction method, the interface of the captured strong impact substance can be corrected from the dotted line to the solid line.

Step 6, after solving and updating the distance indication function values of different positions, the sign distance property of the Level-Set equation may not be satisfied any more, so that the distance indication function value of the flow field calculation domain is calculatedReinitializing to make it meetThe particle re-initialization method is as follows:

wherein τ is a virtual time, and Δt of the equation is solved _r And deltat of the original equation is solved, sign is a sign function,

after the re-initialization is completed, byCan obtain time step t ⁿ⁺¹ Strong impact material interface Γ (t) ⁿ⁺¹ )。

And 7, enabling n=n+1, and executing the steps 3 to 6 again until all time steps are solved, and capturing a strong impact material interface of the strong impact compressible multiphase flow.

In addition, as described above, when the interface of the strong impact compressible multiphase fluid is severely deformed, some areas lack enough particles, and some areas accumulate the particle numbers, so that the particle numbers required to be arranged in the conventional particle re-initialization method far exceed the particle numbers which can be used for correcting the interface in the calculation, a large amount of resources are wasted, and the calculation efficiency is low. Since initializing the position and number of particles will significantly affect the effect of the interface correction, in order to increase the efficiency of particle utilization and correct the relatively important interface part with limited particles, the present application corrects particles in the fluid computing domain every predetermined time step, or corrects particles in the fluid computing domain when it is determined that the degree of deformation of the strong impact material interface satisfies the predetermined requirement, which can be determined by the curvature change condition or the change condition of the number of particles in the grid cell. Wherein the method of modifying particles in a fluid computing domain comprises:

on the one hand, according to the current time step t ^m Captured strong impact material interface Γ (t) ^m ) Interface curvature at different local regions, at the high impact material interface Γ (t) ^m ) Particles are added to the passing grid cells, and the more particles are added to the local area with higher interface curvature, namely the particles are added to the area with higher curvature, so that the capture precision of the interface is improved. In one embodiment, the satisfaction is determinedA local region constituted by the coordinates H of (c), and particles are added to the local region. Wherein, |kappa (H, t) ^m ) I is the time step t ^m Strong impact material interface Γ (t) ^m ) Absolute value of curvature at coordinate H, +.>Is the time step t ^m Strong impact material interface Γ (t) ^m ) Average value of absolute values of curvature at different positions,/->Is the coordinate H at time step t ^m And Δh is the minimum value of the pitch of the grid cells, and C is a constant. The larger the constant C, the particle sizeThe smaller the number of particles required, the higher the calculation efficiency, the more the initialization position is biased to a local portion where the curvature of the strong impact material interface is large, but the too large constant C affects the correction accuracy of the strong impact material interface, so that it is necessary to take an appropriate constant C.

On the other hand, the current time step t ^m Captured strong impact material interface Γ (t) ^m ) Particles in the grid cells that did not pass through are deleted. When the interface of the strong impact substance changes, part of grid cells are not penetrated by the interface of the strong impact substance any more, and the particles left in the grid cells need to be deleted, and the method for deleting the particles is as follows: generating virtual particles I at a distance from the particle along its normal direction ₁ Generating virtual particles I at the same distance in opposite directions ₂ . Comparison I ₁ and I₂ The distance at which the sign of the function value indicates, if the sign is different, does not delete the particle, otherwise the particle is deleted.

In one example of a two-dimensional single vortex application, assuming a fluid computation domain of X Y E [0,1] × [0,1], a circular interface with a radius of 0.15 is located in the fluid computation domain (0.50, 0.75) at the initial time, the flow field velocity field is:

the two-dimensional single vortex flow has the greatest tensile deformation of the interface at t=4.0, and the interface returns to the circular state at the initial moment at t=8.0.

In the interface capturing by the method of the present application, the interface of the strong impact substance captured at t=4.0 is shown in fig. 3, and the interface of the strong impact substance captured at t=8.0 is shown in fig. 4. As can be seen from comparison, the high impact material interface captured at t=4.0 produces a maximum tensile interfacial deformation in which the elongated filament features are also clearly captured. The strong impact material interface captured at t=8.0 is restored to the original circular state, and the good circular shape is maintained.

In another example of application of the explosion process of single cavitation in the infinite domain, it is assumed that the fluid computation domain xye [ 1.0X 1.0 ]]The radius of the explosive cavitation bubble is 0.5, which is located at the origin of coordinates of the computational domain. When the interface is captured by the method of the application, the interface is captured at t=1.80×10 ^-4 The schematic diagram of the Interface of the strong impact material (referred to as Interface) and the pressure contour map captured at s is shown in fig. 5, and as the internal gas is extremely compressed, the Interface of the explosion cavitation rapidly moves outwards, and thus a main shock wave propagating outwards and a subsequent series of pressure waves are generated. It can be seen from the figure that the distribution of the pressure contour lines and the interfacial movement of the explosion cavitation bubbles are very accurate, and no obvious numerical oscillation phenomenon exists. Therefore, the method can accurately and clearly capture the interface change, and can accurately and stably capture and process the material interface of the compressible multiphase fluid under the extreme conditions of strong impact such as underwater explosion by combining an effective interface boundary processing algorithm (for example, a virtual fluid correction method).

The above is only a preferred embodiment of the present application, and the present application is not limited to the above examples. It is to be understood that other modifications and variations which may be directly derived or contemplated by those skilled in the art without departing from the spirit and concepts of the present application are deemed to be included within the scope of the present application.

Claims (9)

1. The high-precision capturing method for the high-impact material interface based on the particle level set is characterized by comprising the following steps of:

grid division is carried out on a flow field calculation domain of the strong-impact compressible multiphase flow to obtain a plurality of grid units;

determining a time step t according to the constructed Level-Set equation ⁰ Strong impact material interface Γ (t) ⁰ ) The passing grid cells are used as interface grids, and particle information of particles in each interface grid is initialized;

at any time step t ⁿ According to time step t ⁿ Particle information of (a) and time step t ⁿ Is attracted to the strong impact material interface Γ (t) ⁿ ) N is a parameter with a start value of 0;

performing first-order dispersion of time dimension by using a semi-Lagrangian method, performing dispersion of space dimension by using the semi-Lagrangian method or a finite volume method, and solving a Level-Set equation and a particle transport equation to obtain a time step t of each grid point of each grid unit ⁿ⁺¹ Distance indication function value of (2) and time step t ⁿ⁺¹ Particle information of (2);

at time step t according to each grid point ⁿ⁺¹ Distance indication function value of (c) and time step t ⁿ⁺¹ Determining escape particles and obtaining projections of the escape particles on grid point normal lines of the grid cells, and correcting the grid points at time step t ⁿ⁺¹ Distance indication function value of (2);

reinitializing the distance indication function value of the flow field calculation domain and obtaining a time step t ⁿ⁺¹ Strong impact material interface Γ (t) ⁿ⁺¹ )；

Let n=n+1 and execute the time-dependent step t again ⁿ Particle information of (a) and time step t ⁿ Is attracted to the strong impact material interface Γ (t) ⁿ ) And the steps are carried out until all time steps are solved, and the capture of the strong impact material interface of the strong impact compressible multiphase flow is completed.

2. The method for capturing a high-precision impact material interface according to claim 1, wherein the correction grid point is at time step t ⁿ⁺¹ The distance indication function value method of (2) includes:

determining each grid point of a grid unit where escape particles are located, determining an intersection point of a line connecting the grid point and a particle center of the escape particles on a boundary of the escape particles for any one grid point, calculating coordinates of a projection point of the intersection point on a normal line of the grid point, and correcting the grid point at a time step t by using particle information of the escape particles when the coordinates of the projection point are located in the grid unit where the escape particles are located ⁿ⁺¹ Distance of (2)Indicating the function value.

3. The method for capturing the interface of the high impact material with high precision according to claim 2, wherein the coordinate is X _P Radius r _P The coordinates of a projection point of an intersection point of a connecting line of the grid point and the particle center of the escape particle on the boundary of the escape particle on the normal line of the grid point are determined as follows:

X′＝X+γproj _n (X _P -X)；

wherein ,proj _n (X _P -X) represents (X) _P X) onto the normal n of the grid point with coordinates X,distance indication function value based on grid point with coordinate X>A determined normal.

4. The high-precision capturing method of a high-impact material interface according to claim 2, wherein the correction grid point is at time step t ⁿ⁺¹ The distance indication function value method of (2) includes:

when the escaping particles are escaping positive particles, determining that the escaping positive particles are correct values of grid points nearbyAnd according to->At time step t for the grid point ⁿ⁺¹ Distance indication function value +.>Correcting;

when the escaping particles are escaping negative particles, determining that the escaping negative particles are correct values of grid points nearbyAnd according to->At time step t for the grid point ⁿ⁺¹ Distance indication function value +.>And (5) performing correction.

5. The high-precision capturing method of a high-impact substance interface according to claim 1, characterized in that the high-precision capturing method of a high-impact substance interface further comprises:

particles in the fluid computing domain are corrected every predetermined time step, or are corrected when it is determined that the degree of deformation of the high impact material interface satisfies a predetermined requirement.

6. The high-precision capture method of a high impact material interface of claim 5, wherein the method of modifying particles in the fluid computing domain comprises:

according to the current time step t ^m Captured strong impact material interface Γ (t) ^m ) Interface curvature at different local regions, at the high impact material interface Γ (t) ^m ) Adding particles in the passing grid cells, adding more particles to the local area with higher interface curvature, and taking the current time step t ^m Captured strong impact material interface Γ (t) ^m ) Particles in the grid cells that did not pass through are deleted.

7. The high-precision capture method of a high impact material interface of claim 6, wherein the method of adding particles in the flow field calculation domain when re-initializing the particles comprises:

determining satisfaction ofA local region constituted by coordinates H of (c) and adding particles to the local region;

wherein, |kappa (H, t) ^m ) I is the time step t ^m Strong impact material interface Γ (t) ^m ) The absolute value of the curvature at the coordinate H,is the time step t ^m Strong impact material interface Γ (t) ^m ) Average value of absolute values of curvature at different positions,/->Is the coordinate H at time step t ^m And Δh is the minimum value of the pitch of the grid cells, and C is a constant.

8. The high-precision capturing method of a high-impact material interface according to claim 1, wherein the method for performing first-order dispersion of a time dimension and a space dimension by using a semi-lagrangian method and solving a Level-Set equation comprises:

performing first-order dispersion of space dimension on the flow field calculation domain, and determining coordinates G of grid points of the ith row and the jth column _i,j = (iΔx, jΔy), and coordinate G _i,j Speed atΔx is the unit step in the row direction, Δy is the unit step in the column direction, u _i,j Is the velocity in the row direction, v _i,j Is the speed along the column direction, i and j are parameters;

performing first-order dispersion of time dimension on the time step, and determining any time step t ⁿ Time of [ n.DELTA.t, DELTA.t ]Unit steps of the inter-dimension;

determining the coordinates G _i,j At time step t ⁿ⁺¹ The distance indication function value of (2) is:

wherein ,representing the coordinates G _r+1,s+1 At time step t ⁿ Distance indication function value,/->Representing the coordinates G _r,s+1 At time step t ⁿ Distance indication function value,/->Representing the coordinates G _r+1,s At time step t ⁿ Distance indication function value,/->Representing the coordinates G _r,s At time step t ⁿ Distance indication function value of (2);

9. the high-precision capture method of a high-impact material interface according to claim 1, wherein the method of performing the dispersion of the spatial dimension by using the finite volume method comprises:

the constructed Level-Set equation isObtaining a spatial discretization Level-Set equation based on a finite volume methodGradient of->The semi-discrete form of the Level-Set equation is obtained as

wherein ,A_f Is the area of the calculation unit surface, V _cell To calculate the volume of the cell, n _f To calculate the unit external normal of the cell surface, ρ is the medium density, u is the flow velocity,is a distance indication function value and faces is a set of computational element planes.