Fluid simulation program, fluid simulation method, and fluid simulation device

A fluid simulating method performed by a computer, the method comprising:

• extracting, based on positional information included in particle data of particles, including fluid particles and wall boundary particles related to a boundary with a wall, during a predetermined time period, a first particle from among the wall boundary particles with a predetermined value or less of distance from a fluid particle among the fluid particles and a second particle with the predetermined value or less of distance from the first particle from among the wall boundary particles excepting the first particle;
• setting a boundary condition of a pressure Poisson equation for calculating pressure to be applied to each of the particles;
• calculating the pressure to be applied to each of the particles, based on the first particle and the second particle;
• and
• calculating the particle data of the particles during a next time period based on the pressure,
• the boundary condition includes that the first particle is set to a fluid particle whose velocity is a predetermined value and that pressure to be applied to the second particle is 0.

A fluid simulating apparatus comprising:

• a memory, and
• a processor coupled to the memory and configured to perform a process including:
• extracting, based on positional information included in particle data of particles, including fluid particles and wall boundary particles related to a boundary with a wall, during a predetermined time period, a first particle from among the wall boundary particles with a predetermined value or less of distance from a fluid particle among the fluid particles and a second particle with the predetermined value or less of distance from the first particle from among the wall boundary particles excepting the first particle;
• setting a boundary condition of a pressure Poisson equation for calculating pressure to be applied to each of the particles;
• calculating the pressure to be applied to each of the particles, based on the first particle and the second particle;
• and
• calculating the particle data of the particles during a next time period based on the pressure,
• the boundary condition includes that the first particle is set to a fluid particle whose velocity is a predetermined value and that pressure to be applied to the second particle is 0.

A fluid simulating apparatus comprising:

• a memory storing instructions;
• a processor coupled to the memory and configured to execute the instructions to perform a process of:
• detecting a plurality of particles including fluid particles and wall boundary particles related to a boundary with a wall in a fluid;
• determining that one or more first particles of the plurality of particles are free fluid particles;
• classifying one or more second particles of the free fluid particles as surface particles from which a neighboring particle is at a distance greater than an influence radius in at least one direction, and one or more third particles of the free fluid particles as internal particles which have neighboring particles at a distance equal to or less than the influence radius in all directions;
• setting a boundary condition of a pressure Poisson equation to be applied to each of the plurality of particles based on the determining and the classifying so that a convergence of a solution is obtained when each of the free fluid particles flows in a gap of the fluid;
• calculating pressure to be applied to each of the plurality of particles, based on the one or more first particles and the one or more second particles;
• and
• calculating particle data of the one or more particles during a predetermined time period based on the pressure.