X-ray measurements of shock-induced mixing at an air/xenon interface

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7264517

Bonazza, R

A new experimental technique to measure the density of a high atomic number gas at an interface has been development and demonstrated based on the absorption of X-rays by the high atomic number gas. It was implemented in a vertical square shock tube for the study of shock-accelerated air-xenon interfaces. These were prepared by retracting a metal plate initially separating the two gases, prior to the release of the shock wave. Interfaces of two types, quasi-sinusoidal and nominally flat, were examined. The objects of study were the amplitude of large wavelength (25-100 mm) perturbations on the interface, and the thickness of the interface. An integral definition for the interface was adopted. Experiments were performed to image interfaces having interacted with the incident shock, the incident and the reflected shock, or a series of weak waves reverberating between the interface and the shock tube end wall. The results for the growth rates of the amplitudes were compared against a model based on the linear theory: The measured values are larger than the predicted ones in the case when the interface only interacts with the incident and the first reflected shocks. They are smaller than the theoretical ones in the case of multiple reverberations. The interface thickness exhibits essentially no growth upon interaction with the incident shock. The interaction of the reflected shock with the turbulent boundary layer behind the incident one generates random acoustical disturbances which cause thickness growth. The thickness growth rates of nominally flat interfaces are larger than those found at GALCIT is a schlieren visualization experiment, in the case of two shock interactions. They are smaller in the case of multiple interactions. In the case of two shock interactions, wall vortices generated by the interaction of the reflected shock with the boundary layer behind the incident one severely affected the measurements. A correction was proposed to account for this effect.

• Research Organization: California Inst. of Tech., Pasadena, CA (United States)
• OSTI ID: 7264517
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
AIR
ELEMENTS
FLOW VISUALIZATION
FLUIDS
GASES
INTERFACES
MIXING
NONMETALS
RARE GASES
SHOCK TUBES
SPECTRA
X-RAY SPECTRA
XENON