Simulation method and simulation apparatus

1. A non-transitory computer-readable recording medium having stored therein a simulation program causing a computer to execute a process comprising:

calculating a flow rate and a water level of a continuum at each grid point in a grid which is generated by dividing a two-dimensional plane as a planar view of a first region into predetermined sections, on the basis of input data;

expressing the continuum in a second region contained in the first region as an assembly of particles; and

subjecting a state of the each particle to a three-dimensional analysis based on the calculated flow rate and water level.

2. The non-transitory computer-readable recording medium according to claim 1 , wherein the process further comprises:

generating an initial condition and a boundary conditions on the basis of the calculated flow rate and water level; and

analyzing the state of the each particle on the basis of the generated initial condition and the boundary conditions.

3. The non-transitory computer-readable recording medium according to claim 1 , wherein the process further comprises:

receiving an input of initial values of the flow rate and water level of a continuum at each grid point on a two-dimensional plane in the first region;

calculating temporal differentiation of a water level at the current step at the each grid point, and subjecting the water level at the current step to temporal integration on the basis of the calculated temporal differentiation of the water level to calculate a water level at the next step;

calculating temporal differentiation of a flow rate at the current step at the each grid point, and subjecting the flow rate at the current step to temporal integration on the basis of the calculated temporal differentiation of the flow rate to calculate a flow rate at the next step; and

repeating the calculation of the water level and the flow rate at the next step until a first predetermined step is reached.

4. The non-transitory computer-readable recording medium according to claim 1 , wherein the process further comprises:

calculating an acceleration at the current step for the each particle according to an equation of motion, and subjecting a speed at the current step to temporal integration according to the calculated acceleration to calculate a speed at the next step;

calculating temporal differentiation of a density at the current step for the each particle according to a continuity equation, and subjecting the density at the current step to the temporal integration according to the calculated temporal differentiation of the density to calculate a density at the next step;

calculating a pressure at the next step for the each particle using a equation according to the calculated density at the next step;

subjecting a position coordinate at the current step for the each particle to temporal integration with the calculated speed at the next step to calculate a position coordinate at the next step; and

repeating the calculation of a speed, a density, a pressure, and a position coordinate at the next step until a second predetermined step is reached to analyze the state of the each particle.

5. The non-transitory computer-readable recording medium according to claim 1 , wherein the process further comprises:

using a speed of a continuum at each grid point on the two-dimensional plane in the first region as a speed of the particle existing at a region boundary at a specific distance from a boundary in the second region.

6. The non-transitory computer-readable recording medium according to claim 1 , wherein the process further comprises:

erasing a particle flowing out across a region boundary at a specific distance from a boundary in the second region;

when a volume of the continuum flowing into the region boundary exceeds a predetermined volume, generating new particles to analyze the state of the particles.

7. A simulation method comprising:

calculating a flow rate and a water level of a continuum at each grid point in a grid which is generated by dividing a two-dimensional plane as a planar view of a first region into predetermined sections, on the basis of input data;

expressing the continuum in a second region contained in the first region as an assembly of particles;

subjecting a state of the each particle to a three-dimensional analysis based on the calculated flow rate and water level; and

storing results of the analysis in a memory.

8. A simulation apparatus comprising:

a two-dimensional analysis processor that determines a flow rate and a wave height of a continuum at each grid point in a grid which is generated by dividing a two-dimensional plane as a planar view of a first region into predetermined sections, on the basis of input data;

a three-dimensional analysis processor that performs a three-dimensional analysis on a second region contained in the first region to analyze the state of each particle in expression of the continuum as an assembly of particles, on the basis of data calculated by the two-dimensional analysis processor.