Published 4 issues per year
ISSN Print: 1065-3090
ISSN Online: 1940-4336
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LIQUID CRYSTAL VISUALIZATION OF THE VORTEX FLOW FIELD WITHIN A YAWED RECTANGULAR CAVITY AT MACH 2
ABSTRACT
A wind tunnel investigation was carried out to examine the surface flow and skin friction distribution within a yawed cavity having a rectangular aspect ratio of 11.79 and a width/depth ratio of 2. The cavity was placed flush with a ground plane and subjected to a turbulent boundary layer flow at a Mach number of 2 and a Reynolds number of 7.3 × l04, based on momentum thickness. The data obtained were video recordings of liquid crystal surface coatings that changed color with shear stress and with changes in yaw angle. It was found that the crystals could provide some assistance in describing the type of fluid motion that occurs in open and closed types of cavities. At low angles of yaw, the fluid motion is one of low shear, whereas at the higher yaw angles, large shear stress areas within the cavity are observed. This is accompanied by increased recirculation regions near the upstream end of the cavity at high yaw angles, with several different vortices being set up at the downstream end to eject excess fluid.
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Naughton Jonathan W., Sheplak Mark, Modern developments in shear-stress measurement, Progress in Aerospace Sciences, 38, 6-7, 2002. Crossref