Hi, I am having trouble find information on the following topic, I think mostly in part because I don't know the correct terminology. Basically, I have a number of particles that are falling at their terminal velocities within a gaseous fluid, and turbulent velocity fluctuations in the fluid itselfs occur which transfer momentum to these particles. I was wondering if there is some theory that might describe how much momentum these particles would extract from the fluid. (The turbulent theory used is based on continuity assumptions of variables such as velocity, though the particles are discrete -- I think that is what is confusing me.) Thanks in advance for any help.