Simulation for Inviscid Sub-Keplerian Flows and Shocks

Abstract

We scan the parameter space spanned by the specific energy and the angular momentum of the inflow and compare the time-dependent solutions with those obtained from theoretical considerations. We found several important results: (a) The time-dependent flow behaves close to a constant height model flow in the pre-shock region and a flow in vertical equilibrium in the post-shock region. (c) The infall timescale in the post-shock region is several times longer than the free-fall timescale. (b) There are two discontinuities in the flow, one being just outside of the inner sonic point. Turbulence plays a major role in determining the locations of these discontinuities. (d) The two discontinuities oscillate with two different frequencies and the post-shock flow behaves as a coupled harmonic oscillator. A Fourier analysis of the variation of the outer shock location indicates a higher power at the lower frequency and lower power at the higher frequency. The opposite is true when analysis of the inner shock is made. These behaviours will have implications in the spectral and timing properties of black hole candidates.