Group Summary: Experiments

Abstract

Two experimental investigations were conducted in conjunction with the workshop in NASA Langley facilities at opposite extremes of the fluid dynamics flow spectrum. The first is an incompressible study dealing with the effect of periodic, distributed roughness on the rotating disk’s stationary and traveling cross-flow modes. The other is a high-speed, compressible study dealing with various attempts to excite and measure controlled disturbances in the boundary layer of a blunt, conical body in a Mach 6 quiet tunnel. Each experiment was purposefully limited in scope to allow the work to be completed during the scheduled workshop, however, the experimental outcomes varied greatly. In the case of the rotating disk, the inherently uncomplicated nature of the apparatus along with careful preplanning helped to delivered significant new information in a very productive manner. In the case of the Mach 6 study, despite similarly long and extensive preparation, numerous factors conspired to limit productivity. Several “surprises” were manifest during the workshop in peripheral areas such as starting characteristics of the wind tunnel, initial failure of the disturbance generator to follow successful “bench top”