Experimental investigation of supersonic flow over two cavities in tandem

A study is presented on supersonic flow over two rectangular cavities arranged in tandem at Mach 1.5, 2.5, and 3.5. Both time-mean and unsteady aspects of the flowfields are examined. For the purposes of this paper, cavities are chosen in which the oscillatory properties are due either to a fluid resonant phenomenon or to a fluid dynamic phenomenon. These are defined as type A and type B cavities, respectively. At Mach 1.5 and 2.5, the flow in a type A cavity is found to be completely altered by a preceding type B cavity. When the type B cavity is preceded by another type B cavity, only the level of the unsteady pressures and the high frequency modes of the oscillation are affected. When type A cavity precedes a type B cavity, only small quantitative changes are noted in the oscillatory behavior. The influence of the spacing between the two cavities is also addressed.