中文说明：用计算流体力学方法模拟粒子碰撞，可以自定义各种参数包括粒子数，粒子密度，半径等。 可用于重力坐标系或者无重力空间。
English Description：
Particle collisions are simulated using computational fluid dynamics method, you can customize a variety of parameters including the number of particles, the particle density, RADIUS and so on. Can be used to coordinate of gravity or gravity-free space.