Supersonic Windtunnel Digital Measurement and Imaging Laboratory

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Equipment to improve an undergraduate laboratory in the thermal and fluid sciences will be provided. In light of our nation's renewed interest is supersonic and hypersonic flight, the teaching of compressible fluid mechanics is of paramount importance. In addition, the rapid pace of technology has given the science and engineering community new tools with which the student must be familiar. The Supersonic Windtunnel Digital Measurement and Imaging Laboratory satisfies these two needs in a unique way. The heart of the project is a high Reynolds number, supersonic windtunnel, exhausting to atmospheric pressure and capable of attaining Mach 2.5 and Reynolds numbers exceeding one million. It is a blowdown facility that relies on modern, fast-response, computer-controlled instrumentation. Since the typical run time is only a few seconds, only instruments capable of quickly making and storing measurements are useful. The main instruments required are a multiple-channel pressure scanner, a digital computer for control, data acquisition, and analysis, and the equipment making up the unique digital imaging unit. The purpose of this last unit is to take snapshots of the flow in one of several useful optical modes (e.g., Schlieren to observe the shock structure, and shadowgraphy for single gas turbulence or multiple gas mixing). A pulse YAG laser illuminates the flow periodically, then the image is captured by a CCD camera, digitized, and stored in the controlling computer which allows subsequent image processing of the data.