Gas Flow Structure in Binary Systems with Mass Exchange Driven by Stellar Wind

Results of calculations of the flow structure in binary systems with mass exchange driven by stellar wind are presented. 2D simulations have been carried out using the Roe-Oscher scheme. The fine grid we used allowed us to detect the details of the flow structure. In particular, it was found out that solutions with the wind velocity V of the order of the orbital velocity of the system Vs are unstable: in solutions with V<Vs -- the steady accretion disk takes place and if V>Vs -- the cone shock forms. Consideration of the minor variations of the wind velocity V around Vs shows that they can influence greatly the flow structure causing transition from disk accretion to the accretion from the flow. During the flow rearrangement period (the accretion disk destruction) the accretion rate increases in dozens times for a short time (~0.1 of the orbital period of the system). This change can result in the drop-off of the gas from the accretor that is usually associated with activity in these systems.