Julian Talbot - LPTMC-CNRS #
Kinetic Theory of a Frictional Granular Motor #
We investigate the influence of dry friction on an asymmetric, granular
piston of mass M composed of two materials  undergoing inelastic 
collisions with bath particles of mass m. Numerical simulations of the 
Boltzmann-Lorentz equation reveal the existence of two scaling regimes 
depending on the friction strength. In the large friction limit, we 
introduce  an exact model giving the  asymptotic behavior of the 
Boltzmann-Lorentz equation. For small
friction and for large mass ratio M/m, we derive a Fokker-Planck
equation for which the exact solution is also obtained. Static friction 
attenuates the motor effect and results in a discontinuous velocity 
distribution.