# Physics about particles behave (dust simulator)

1. May 9, 2006

### Vivian_H

Dear all,

I have some problems to do a dust simulator. Now there are a lot of physics and math questions I should figure out, then I can do the particle behavior calculation correctly.

What I want to do:
A simple scene contains a floor and a box. When the user press the direction key “Left” “Right” “Up”(go North) “Down”(go South) and that can control the moving speed and direction of the box on the floor.
When the box is moving, there are some particles (dust) behind it. Those particles’ position and movement should look like dust.

Overall, it will be a simple simulator and I don’t consider particle stickiness, collision and wheels effect now. Is anyone familiar with the particle physics like Reynolds Number, Navier-Stokes Equation, Laminar Flow, computational fluid dynamics etc.?

Thank you,
Vivian

2. May 9, 2006

### Astronuc

Staff Emeritus
That sounds like a typical particle simulator using a Monte Carlo method.

One would start with N (x, y, z) positions and N (vx, vy, vz) and bascially follow the particles calculating a new position after each time increment.

If one simulating dust particles in a gas medium, then one has to model the bulk movement of air with the appropriate equations. Then one models particle-fluid or fluid-fluid interaction.

The box is a boundary condition, which is stationary (fixed) or moving (time dependent).

edit: I was going to add that this seems to be a question for Clausius2, and here he is.

Last edited: May 10, 2006
3. May 9, 2006

### Clausius2

I don't understand that. Can you make it clearer? What do you mean with "behind" and with "dust". What is "dust" for you?. Do you mean something random?. Even the aerodynamics of a box in a cloud of dust is deterministic. How do you want to track particle trajectories? One by one? or do you want to treat the "dust" as a cloud (scalar)?