The Effects of Incoming Boundary Layer Thickness on Unsteady Shock-Induced Turbulent Separations Induced by Cylinders
Abstract
Wall pressure fluctuations were measured under the unsteady separation shock/turbulent boundary layer interaction induced by unswept circular cylinders to determine the role of the incoming turbulent boundary layer thickness on the shock motion. Measurements were taken in a high Reynolds number, Mach 5 flow in the turbulent boundary layer developed on the wind tunnel floor. The wall temperature was adiabatic. High frequency response, miniature pressure transducers were mounted flush with the tunnel floor to measure the pressure fluctuations caused by the shock motion. A conditional sampling algorithm was used to separate the pressure fluctuations due to the shock motion from those fluctuations associated with the incoming and downstream turbulent boundary layer. Standard time series analysis techniques were used to analyze the data. Results show that the turbulent boundary layer has only second order effects on the frequency of the separation shock. Shock frequencies are at least one order of magnitude less than the large eddy frequency of the turbulent boundary layer. The low frequency pressure fluctuations of the separated region are within the same frequency range as the shock frequencies. These pressure fluctuations are a possible cause of the shock motion and warrant further investigation. Keywords: Hypersonic flow separation; Unsteady flow. Theses
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA196190
Entities
People
- Douglas R. Smith
Organizations
- Air Force Institute of Technology