Particle simulator and method of simulating particles

A particle simulator simulating the behavior of particles in a particle group having a diameter distribution in a work area through calculation of positions and velocities of the particles based on values of contact forces generated between the particles and other particles in the particle group, the particle simulator comprising:

• input means for inputting particle information including position information and velocity information of the particles;
• particle-information storing means for storing the particle information;
• assigning means for assigning specific information items to the particles to identify the particles in an order in accordance with the position information;
• contact-candidate selecting means for selecting target particles from particle group in the ascending order of the specific information items and selecting non-target particles paired with the target particles as contact-candidate pairs, the non-target particles presumably being in contact with the target particles and having a diameter smaller than the diameter of the target particles;
• contact-force calculating means for calculating the values of contact forces generated between the two particles in the contact-candidate pairs selected by the contact-candidate selecting means based on the position information and the velocity information of the paired particles and storing information items of the calculated values of contact forces in an order corresponding to the order of the contact-candidate pairs in contact-force tables;
• contact-force-reference-table preparing means for preparing contact-force-reference tables including reference information used to refer to the contact-force tables to retrieve the values of contact forces generated between target particles and neighboring non-target particles, wherein, for a given target particle, non-target particles having a diameter greater than the diameter of the target particle are considered;
• integral-contact-candidate-number calculating means for calculating integral contact-candidate numbers, wherein an integral contact candidate number is an integer value denoting the number of non-target neighboring particles associated with a target particle having a diameter smaller than the diameter of the target particle;
• contact-force-sum computing means for extracting the values of contact forces generated between target particles and non-target particles having a diameter greater than the diameter of the target particles by using the reference information in the contact-force-reference tables, extracting the values of contact forces generated between the target particles and non-target particles having a diameter smaller than the diameter of the target particles by specifying the storage positions of the values of contact forces in the contact-force tables using the integral contact-candidate numbers, and computing the sum of contact forces for each target particle using the extracted values of contact force;
• calculating means for calculating new position information and velocity information of the target particles based on the values of contact forces of the particles calculated by the contact-force-sum computing means;
• and
• particle-information updating means for updating the particle information stored in the particle-information storing means using the new position information and velocity information calculated by the calculating means.