IV. Experiments on supersonic flow past bodies of revolution with annular gaps of rectangular section

Abstract

Summary The supersonic flow past flat-nosed circular cylinders with annular gaps of rectangular section was investigated by schlieren photography and pressure measurements. The length of the gap was varied in small steps, from low values, where the gap formed a single dead-air region, to high values, where the flow in the gap consisted of two dead-air regions with an intermediate region of attached How. In particular, the length of the gap for which the How changed from the type with one to the type with two dead-air regions was determined. The experiments throw some light on the details of the flow in the dead-air regions, and it was found that the velocities inside these regions may be of considerable magnitude. Qualitative information was obtained about the effects of the length of the gap on the drag caused by the gap.