Large Dynamic Range Shock Wave Measurements

An optical sensor capable of producing 3-dimensional time resolved density maps characteristic of shock wavefronts at Mhz sampling rates is proposed. Each map is obtained from simultaneous measurements obtained with a novel refractometer capable of measuring integrated density fluctuations in air to better than 1 part in 3500 per centimeter path length at 1Mhz with good signal to noise (S/N=10). the data are tomographically reconstructed to produce a series of high speed images able to be viewed consecutively. the proposed system is based on the success ful combination of two sophisticated technologies which can be implemented using inexpensive mass produced components. The resulting sensor can be produced at a low enough cost to consider a realistic tomographic system as well as making it "attractive as a commercial product. As part of the Phase I effort, a feasibility experiment" demonstrating high temporal resolution with a limited angle data set will be performed; the Phase II effort would result in a field ready prototype. The proposed technology would have application in the aerospace industry for the monitoring of sonic disturbances, would provide a unique capability for wind tunnel and combustion chamber facilities, and have wide spread application to several other industrial markets such as non-invasive leak detection for process m control and imaging of gas clouds.