We consider some recently developed unconditionally stable numerical scheme
s for the Boltzmann equation, called Time Relaxed (TR) schemes. They share
the important property of providing the correct fluid dynamic limit. Stabil
ity analysis of the schemes is performed, and the A-stability and L-stabili
ty of the schemes is studied. Monte Carlo methods based on TR discretizatio
ns are briefly reviewed. In particular, first and second order particle sch
emes are compared with a hybrid scheme, in which the equilibrium part of th
e distribution is described analytically.