Properties of the mass stream– accreting matter interaction in two Double White Dwarfs

We investigate the mass transfer properties at the evolutionary stage after the mass transfer being started, in two Double White Dwarfs binary stars – CR Boo and V 803 Cen. Both are AM CVn stars objects: short period binaries; helium-rich accreting material; The mass transfer is considered to be realized via the Roche-lobe overflow; Solutions of the mass transfer stability by the dynamical stability criteria; The accretion efficiency of two objects is estimated. The obtained values are very low.