Density distribution configuration and development of vortical patterns   in accreting close binary star system
  We investigate the problem of structures formation in accretion disc zone, resulting from the tidally interaction in close binary star system. We aim to examine the area where the incoming flow meets the matter around secondary star and the resulting effects throughout the accretion disc. The research is based on employment of the fluid dynamics equations in conjunction with numerical simulations leading to the design of graphical models of accretion processes. For the simulation we propose box-framed sharing schemes. (i) The tidal transfer of matter through the inner Lagrangian point in close binary stars disturbs the flow in disc's zones and outer disc area. Calculations on the perturbed parameters of density and velocity reveal formation of a thickened zone in the contact area of interacted flows. It appears to be stable for a number of periods and is unaffected by rotation and dissipation processes. (ii) The results also show development of undulations, which grow to vortical patterns in the accretion disc's zone. It is confirmed that under the influence of tidal wave the conditions of reconfiguring of accretion flow structure are generated. 
Daniela Boneva, Lachezar Filipov
astro-ph.SR