Abstract
Effect of freestream turbulence on concave and convex surfaces with mild curvature (5/R-0.016 and 0.022 for convex and concave surfaces respectively) and pressure gradient was examined. Turbulence levels of 3.6 and 8.5 percent were generated with the help of two grids of 93 and 71 percent porosity respectively. Skin friction was determined from the measured boundary layer profiles. A rake of Preston tubes was used to measure spanwise skin friction distribution on both surfaces. Goertler vortices observed on concave surface were present even at higher turbulence level. The curvature and pressure gradient effect was not strong enough to cause a substantial growth of the internal layer. Measurements in the recovery section showed that the boundary layer did not recover from the curvature effect. Effect of outer layer manipulation on concave wall was also studied by using a Large Eddy Breakup device. The skin friction increased on the concave wall despite using the device showing a predominant effect of concave curvature. However, in the recovery section, a decrease in skin friction indicated the effectiveness of the device.
Syed, Irshad Hussain (1995). The effect of freestream turbulence and outer layer manipulation on turbulent boundary layer flow on surfaces with convex and concave curvatures. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1995 -THESIS -S94.