Vorticity Generation by Shock Propagation through Bubbles in Air.
Abstract
We use numerical solutions of the fluid equations for conservation of mass, momentum, and energy to study the interaction of a planar shock with a local, discrete inhomogeneity in the ambient medium. We study the effects of both geometry and distortion of the local sound speed by considering the nonuniformity to be a cylindrical of spherical bubble which has either a higher or lower density than the ambient gas. The Mach number of the shock is 1.2, the ambient gas is air, and the pressure is 1 atmosphere. The passage of the shock through a bubble generates vorticity at the boundary of the bubble. This vorticity produces a jet of ambient gas through the bubble, and as a consequence, the vorticity rolls up into a vortex filament pair (cylindrical bubble) or a vortex ring (spherical bubble). We discuss the theoretical treatment of this nonlinear interaction of the vorticity with itself and the relationship of our work to other theories. We relate our results to recent experiments of Haas and Sturtevant, in which helium and freon bubbles were used to simulate the local departures from ambient density. Keywords: Shock/bubble interactions; Non-uniform gases.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 14, 1986
- Accession Number
- ADA176610
Entities
People
- J. Michael Picone
- Jay Paul Boris
Organizations
- United States Naval Research Laboratory