Three-dimensional fluid simulation method
A three-dimensional fluid simulation method is disclosed wherein: a first mesh of a flow domain non-uniformly split with respect to each of three degrees of freedom is defined; a second mesh uniformly sprit with respect to only one of the three degrees of freedom but non-uniformly with respect to other two degrees is defined; an object model is set in the first mesh and a motion equation is formed and calculated to obtain fluid velocity; based on the fluid velocity, flow imbalance is computed for each cell; based on the flow imbalance, fluid pressure correction equation is formed; the flow imbalance is mapped onto the second mesh and the fluid pressure correction is computed; the fluid pressure correction is mapped onto the first mesh; and until the flow imbalance and motion equations are converged the computation is repeated.
1. A three-dimensional fluid simulation method for analyzing a flow of fluid around an object by the use of a computer comprising:
a process (a) in which a first mesh of the entirety of a three-dimensional space where the fluid flows, is defined in the computer, wherein the first mesh is defined by non-uniformly splitting the three-dimensional space with respect to each of three degrees of freedom of the three-dimensional space;
a process (b) in which a second mesh of the entirety of the three-dimensional space is defined in the computer, wherein the second mesh is defined by non-uniformly splitting the three-dimensional space with respect to two of the three degrees of freedom in the same manner as the first mesh and uniformly splitting the three-dimensional space with respect to the remaining one of the three degrees of freedom;
a process (c) in which an object model of the object is defined in the computer, wherein the object model is defined by splitting the object into a finite number of cells, and the object model is disposed in the first mesh;
a process (d) in which boundary conditions are given and a motion equation relating to the fluid around the object model in the first mesh, is defined, and velocity of the fluid is computed from the motion equation;
a process (e) in which a flow imbalance is computed for each cell in the first mesh based on the obtained velocity of the fluid;
a process (f) in which a pressure correction equation relating to the fluid is defined based on the obtained flow imbalance in the first mesh;
a process (g) in which the obtained flow imbalance in the first mesh is mapped onto the second mesh without the object, and the pressure correction of the fluid is computed on the second mesh; and
a process (h) in which the obtained pressure correction is mapped onto the first mesh with the object, and the fluid pressure on the first mesh is updated based on the mapped pressure correction, and the velocity of the fluid is obtained based on the updated fluid pressure,
wherein the processes (d)-(h) are repeated until the flow imbalance is converged.
2. The three-dimensional fluid simulation method according to claim 1 , wherein
the mapping in the process (g) is made by the use of a numerical interpolation method.
3. The three-dimensional fluid simulation method according to claim 1 or 2 , wherein
each of the first mesh and the second mesh is an orthogonal mesh.
4. The three-dimensional fluid simulation method according to claim 1 , wherein
the object is spherical, and the fluid is air.
5. The three-dimensional fluid simulation method according to claim 1 , wherein
the mapping in the process (h) is made by the use of a numerical interpolation method.
6. The three-dimensional fluid simulation method according to claim 1 , wherein
each of the first mesh and the second mesh is an orthogonal mesh in a x-y-z coordinate system, and
in the second mesh, the non-uniform splitting is made in the x-axis direction and y-axis direction and the uniform splitting is made in the z-axis direction.