Effect of Riblets upon Flow Separation in a Subsonic Diffuser
Abstract
This thesis investigates the effect of riblets upon flow separation in a two-dimensional straight-walled subsonic diffuser. Riblets are small flow- aligned grooves which can be attached to an aerodynamic body. Studies involving the application of riblets to turbulent flow over a flat plate have consistently shown a decrease in viscous drag as compared to the same surface without riblets. The purpose of this investigation was to determine the effect applying riblets to the walls of a subsonic diffuser would have upon flow separation in the fluid handling device. For this investigation, it was found separation was indeed delayed in a diffuser employing riblets as compared to a geometrically identical plain diffuser. For the smaller throat widths, this delay was significant, being as high as 250% due to riblets. As the diffuser throat width increased, the delay in flow separation due to riblets decreased. Also evident in the investigation was the strong dependence of flow separation upon throat velocity for the diffuser with riblets.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA203178
Entities
People
- Nathan W. Martens
Organizations
- Air Force Institute of Technology