Three-Dimensional Structure of Transonic Shear Flow Interacting with Shock Wave

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A laser-induced fluorescence (LIF) method has been developed to measure three-dimensional structure and unsteady behavior of transonic shear flows interacting with shock waves. It was applied to flow measurements for the shock-wave/boundary-layr and shock-wave/free-shear-layr interaction problems. Detailed data on the interaction problems obtained by the LIF method were analyzed and compared with numerical simulations to investigate the unsteady three-dimensional behavior of the transonic shear flows interacting with shock waves. As a result, the following conclusions can be drawn :From a three-dimensional temperature distribution measured in a transonic duct flow field with a swept-back bump using a three-dimensional flow measurement system based on the LIF method, highly complicated flow structure in the three-dimensional shock-wave/boundary-layr interaction field was clarified including three-dimensional shock pattern induced by the swept-back bump, shock reflection form on duct walls and flow separation structure in wall boundary layres. It was found that the present measuremennt system offered a powerful diagnoxtic tool for the three-dimensional transonic shear flow interacting with shock waves.The LIF method was applied to an unsteady three-dimensional flow measurement for the shock-wave/free-shear-layr interaction in a supersonic cavity flow. The flow phenomena in the interaction field, namely shear layr separated from the cavity leading edge, detached shock wave at the cabity trailing edge and vortex structure in the cavity were made clear from three-dimensional distributions of time-averaged temperature and temperature fluctuation. Three different types of self-sustained flow oscillation in the supersonic cavity were found out.