NUMERICAL COMPUTATION OF 2-DIMENSIONAL WIND ACCRETION OF ISOTHERMAL GAS

A new numerical algorithm for calculating isothermal wind accretion fl ows has been developed and is applied here to the analysis of the hydr odynamics of two-dimensional plane symmetric accretion flows in wind-f ed sources. Polar coordinates are used to ensure fine resolution near the object. It is found that a thin accretion column is formed which s hows wave-like oscillations. Small accretion disks are formed temporar ily ground the object. Mass accretion rate and angular momentum accret ion rate exhibit quasi-periodic oscillations. The amplitudes of the os cillations depend on the size of the inner boundary, the number of gri d points and the method of calculation. For a smaller size of the inne r boundary, finer grids and more accurate numerical schemes, the ampli tudes of the oscillation become larger.