Currently there is limited or no off-body flow measurement capability in many of Langley's large wind tunnels, including the National Transonic Facility (NTF). Quantitative, multi-parameter flowfield measurements will enable improved understanding of flow physics and provide validation data for computations. Such data may inspire new fluid models (e.g. turbulence models) and would also provide needed boundary conditions for flow computation. The current state of the art technology includes physical probes (pitot, static pressures, thermocouples). Also some laser-based techniques use particles or gases seeded into a flow for velocity measurement. However, probes and seed particles/gases cannot always be used. Sometimes they perturb the flow or impact the facility. Thus there is a significant need for molecular-based measurement techniques for air or N2 flows. Measurements of velocity, density, pressure, temperate and concentration are needed.
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