An Experimental Study of Two-Dimensional Supersonic Jet Impingement on a Flat Plate

摘要

An experimental study of the flow field associated with a two-dimensional, supersonic jet impinging normally on a flat plate is reported. Two wedge nozzles manufactured at the design Mach numbers of 1.75 and 2.75, respectively, were used to provide the jet. Extensive pitot surveys of the free jet were first conducted to determine the quality of the free jet. Results indicate that the simple wedge nozzles were adequate in providing the desired two-dimensional jet in the free expansion configuration. Results of surface pressure measurements and schlieren photographs of the impingement flow indicating the shock patterns are then presented and discussed. Although the results are principally reported for the case of the jet at isentropic exit conditions, some results of underexpanded and overexpanded jets are also included. Some discrepancies between the experiment and the simple theory based in the method of integral relations and the inviscid flow model are noted and discussed. An 'effective' jet Mach number is introduced which accounts largely for the discrepancy between experiments and theory, and its determination is based on the measured stagnation point pressure on the plate surface. (Author)