TITLE:
Numerical Investigation of a Shock Accelerated Heavy Gas Cylinder in the Self-Similar Regime
AUTHORS:
Bing Wang, Jing-Song Bai, Tao Wang
KEYWORDS:
Interficial Instabilities, Vortex Dynamics, Power Laws
JOURNAL NAME:
International Journal of Astronomy and Astrophysics,
Vol.5 No.1,
March
20,
2015
ABSTRACT: A detailed numerical simulation of a shock accelerated heavy gas (SF6)
cylinder surrounded by air gas is presented. It is a simplified configuration
of the more general shock-accelerated inhomogeneous flows which occur in a wide
variety of astrophysical systems. From the snapshots of the time evolution of
the gas cylinder, we find that the evolution of the shock accelerated gas
cylinder is in some ways similar to the roll-ups of a vortex sheet for both
roll up into a spiral and fall into a self-similar behavior. The systemic and
meaningful analyses of the negative circulation, the center of vorticity and
the vortex spacing are in a good agreement with results obtained from the prediction
of vorticity dynamics. Unlike the mixing zone width in single-mode or
multi-mode Richtmyer-Meshkov instability which doesn’t exist, a single power
law of time owing to the bubble and spike fronts follow a power law of tθ with different power
exponents, the normalized length of the shock accelerated gas cylinder follows
a single power law with θ = 0.43 in its self-similar regime obtained from the
numerical results.