how to apply constant velocity to particles during the simulation
 

Dear all,
I am simulating a domain with some particles moving in a certain direction during the whole simulation. My problem is to apply this constant velocity to the particles in the entire domain and during my simulation.

Does anyone have any idea or suggestion?

thanks

As I understood you want to have some particle phase that not to be affected by fluid phase. It is strange. Can you explain more about your case?