Energy and Momentum Transfer via Coulomb Frictions in Relativistic Two   Fluids
  We numerically calculate the energy and momentum transfer rates due to Coulomb scattering between two fluids moving with a relative velocity. The results are fitted by simple functions. The fitting formulae are useful to simulate outflows from active galactic nuclei and compact high energy sources. 
Katsuaki Asano, Shizuo Iwamoto, and Fumio Takahara