Torque on particles
 

Hi all, Hope this question is not too basic.

I'm trying to setup a 2D simulation which include forces on particles flowing in a liquid and I need to include the torques generated on the particles as they approach a solid surface.

I've read some physics books but I'm still not sure if the torques generated are forces or momentum sources and how I shall include them in the force balance of the particles.

Can someone explain me a little?

Thanks

CFD student

Re: Torque on particles
 

This is not intended as an explaination, but rather some ideas for further thought. Assume that these are not point particles, but rather have some extension. Also assume that their presence doesn't perturb the fluid flow. Assume the fluid velocity is zero on the particle surface. Then there might be a net circulation around the particle, proportional to the curl of the velocity field. But the particle may be rotating relative to the curl of the field, so this would produce a shear, and hence a torque, balanced by the rotational inertia of the particle and its angular acceleration. I don't know what sort of boundary layer would be appropriate for these particles. Perhaps someone else has ideas.

Re: Torque on particles
 

As you say I must think about these subjects, seems at first that is more momentum than force that torque must be considered but would like to hear more ideas if someone is interested.

Thanks for the answer.

CFD student