Mechanical Engineering ETDs

Patrick Wayne

Publication Date

2-1-2016

Abstract

This thesis presents an experimental study of instabilities developing from oblique shock wave interaction with a heavy gas column. For these experiments, the gas column consists of pure sulfur hexafluoride infused with ~11% acetone gas by mass. A misalignment of the pressure and density gradients (from the shock wave) results in three-dimensional vorticity deposition on the gaseous interface. This is the main mechanism responsible for the formation of traditional Richtmyer-Meshkov instabilities (RMI). Other instabilities develop along the interface due to shear between the injected material and the post-shock air (moving at piston velocity behind the column). These instabilities present on the leading (with respect to the shock) and trailing edges of the column. On the leading edge, small perturbations are amplified by shear at the interface. This leads to the development of full billows, or ``cat's eye'' vortices, physically indistinguishable from Kelvin-Helmholtz instabilities (KHI). Certain characteristics of the KHI, such as initial instability growth rate and wavelength (lambda), depend on several factors including the Mach number of the shock wave, the shock tube angle of inclination (theta), and the post-shock compressed size of the column.

Keywords

shock, wave, Kelvin-Helmholtz, instability, Planar Laser Induced Fluorescence, oblique

Degree Name

Mechanical Engineering

Level of Degree

Masters

Department Name

Mechanical Engineering

First Committee Member (Chair)

Truman, C. Randall

Sponsors

National Nuclear Security Administration

Document Type

Thesis

Language

English

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