Flow Morphologies of Two Shock-accelerated Unstable Gas Cylinders

Article type: Research Article

Authors: Tomkins, C. | Prestridge, K. | Rightley, P. | Vorobieff, P. | Benjamin, R.

Affiliations: Dynamic Experimentation Division, Los Alamos National Laboratory, Los Alamos, NM87545, USA. | Department of Mechanical Engineering, University of New Mexico, Albuquerque, NM87131, USA.

Abstract: Our highly reproducible shock-tube experiments examine the interaction of two unstable, compressible gas cylinders accelerated by a planar shock wave. Flow visualization shows that the evolution of the double-cylinder flow morphologies is dominated by two counter-rotating vortex pairs, the strength and behavior of which are observed to be highly sensitive to the initial cylinder separation. Simulations of the flow based on idealized vortex dynamics predict grossly different morphologies than those observed experimentally, suggesting that interactions at early time weaken the inner vortices. A correlation-based ensemble averaging procedure permits decomposition of the concentration field into mean and fluctuating components, providing evidence that energy is transferred from the intermediate to the small scales at late time.

Keywords: visualization, Richtmyer-Meshkov instability , shock wave , vortex dynamics

Journal: Journal of Visualization, vol. 5, no. 3, pp. 273-283, 2002