Drag reduction over embedded cavities in Couette flow

✍ Scribed by A.W. Lang; T.J. Johnson

• Book ID: 104048460
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 174 KB
• Volume: 37
• Category: Article
• ISSN: 0093-6413
• DOI: 10.1016/j.mechrescom.2010.04.011

✦ Synopsis

Using a newly developed Couette flow facility with high viscosity oil as the working fluid, drag measurements over a patterned surface consisting of two-dimensional square embedded cavities orientated transversely to the main flow were experimentally obtained. Drag data was then compared to that obtained over a flat plate. Results show that for Re < 15 (where Re is based on the gap height) an appreciable drag reduction of >5% is obtained. This reduction, known as the "roller bearing effect", is due to the formation of embedded vortices within the cavities. Also, as the Re decreases the theoretical Stokes limit of 18% drag reduction is approached.