High-Repetition-Rate Interferometric Rayleigh Scattering for Velocity, Density, and Temperature Meas

Subsonic, transonic, supersonic, and hypersonic ground test facilities are used extensively to evaluate forces and moments as well as surface measurements on test articles required to validate computational tools used to extrapolate wind tunnel data to realistic flight conditions and hardware. The development of fast and noninvasive instrumentation and measurement capabilities that can readily be integrated into the extreme environments is one of several major technological challenges associated with the design, building, and operation of these complex test environments. Accurately mapping velocity flow fields-undoubtedly one of the most critical parameters-remains a significant challenge. In addition, spatially and temporally resolved measurements of other flow parameters such as density, pressure, and temperature are of paramount importance. This proposal offers an integrated package of truly cutting-edge, multidimensional, seedless velocimetry and multi-flow-parameter diagnostics for wind tunnels and ground test facilities. The concepts and ideas proposed are ranging from proof-of-principles demonstration of novel methodologies using 10-100 kHz-rate nanosecond (10-100 nsec) duration burst-mode laser sources for measurements in realistic tunnel conditions. The proposed high-repetition-rate Rayleigh scattering which is suitable for any wind tunnel testing involving various gases is a state-of-the-art technique for analysis of unsteady and turbulent flows.