Boundary-layer receptivity of three-dimensional roughness arrays on a swept-wing

Micron-sized, spanwise-periodic discrete roughness elements are applied to a 45 swept-wing to experimentally quantify the relationship between surface roughness and initial disturbance amplitude for a boundary-layer dominated by crossflow instability. The ASU(67)-0315 is installed in the low-turbulence Klebanoff-Saric Wind Tunnel at Texas A&M University. It has a 1.83 m chord and a pressure minimum at 71% chord. Appliqu roughness arrays are placed near the leading edge to investigate the effectiveness of each roughness height in generating initial disturbance amplitudes. Test parameters include roughness height and chord-Reynolds-numbers of 2.4 to 3.2 x 106. Naphthalene flow visualization, used to determine transition location, and detailed velocity profile scans using hotwire anemometry are provided. When care was taken to measure in the region of linear stability, it was found that the disturbance amplitude varies linearly with roughness height. However, evidence is present that differences in already low turbulence levels influence the receptivity process. 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Boundary-layer receptivity of three-dimensional roughness arrays on a swept-wing Conference Paper