Effects of Pressure Gradients on Turbulent Boundary Layer Flow Over a Flat Plate with Riblets

Download or read book Effects of Pressure Gradients on Turbulent Boundary Layer Flow Over a Flat Plate with Riblets written by Franklin Dement and published by . This book was released on 1999-03-01 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Air Force Institute of Technology Boundary Layer Research Facility test section was modified to create controlled non-zero streamwise pressure gradients. The capability of the modified facility to reproduce theoretical laminar boundary layer velocity profiles and to create a self- preserving flow with an adverse streamwise pressure gradient was verified with three-dimensional laser Doppler anemometry. The effects of streamwise adverse and favorable pressure gradients on turbulent boundary layer flow characteristics (velocity profiles, turbulence and skin friction) and vortex formation over a flat plate with riblets at low speed (U = 5 mIs) were studied. Normal and spanwise velocity profiles for both pressure gradients showed the presence of paired counter-rotating vortices nested within the riblet valleys. These flow structures increased drag and significantly altered near-wall flow compared to a smooth plate turbulent boundary layer. The adverse pressure gradient tended to degrade these vortices as the flow progressed.