Patent ID: 9170185
Filing Date: 2015-10-27
Classification: G01N,G06F

Abstract:
1. A non-transitory computer-readable recording medium having stored therein a simulation program for causing a computer to execute a process for suppressing behaviors including generating an unnatural velocity distribution when simulating a temporal shape change in a fluid, the process comprising: obtaining a position vector and a velocity vector of a particle forming the fluid from a storage unit; calculating, with respect to a fluid model representing the fluid as a collection of particles, a force applied to each particle and a surface tension applied to each particle using the obtained position vector and velocity vector; adding the calculated force applied to each particle and surface tension applied to each particle to the velocity vector so as to update a velocity of each particle; calculating a shape change in the fluid using the updated velocity of each particle; and outputting the calculated shape change to an output unit, wherein is used when updating the velocity of each particle, [Formula 12] including a second term on the right side expressing a pressure gradient term, a third term on the right side expressing a viscous stress term, a fourth term on the right side expressing a gravity term, and a fifth term on the right side which is a force for preventing the distance between particles from becoming too close, to calculate the force applied to each particle, as well as a sixth term on the right side which is a surface tension, and followed by the following calculation: wherein r m ξ, η are constants introduced to calculate a viscous term, wherein (r min is a constant), wherein is applied, and χ i =χ i ( y i *, ε) if a plain surface of y=0 is a wall surface of a solid, wherein g is gravity acceleration, y is a unit vector in the y direction, h expresses an influence radius which is a radius of a spherical area in which a value of a kernel function is non-zero, and W is an overlap of kernel functions used in the SPH method, wherein L( is a renormalization matrix of and if v i s,n = v i n · n ij * v j s,n = v j n · n ij *, wherein are intermediate values of space-time determined by solving the one-dimensional Riemann problem between the particles i and j, the values being determined by a process including: and then calculating each gradient as follows: and wherein r ij *=| r ij *| and using the above quantities, p ij n+1/2 ,v ij n+1/2 are determined as follows: