Boundary-Layer Transition on a Flared Cone in the Texas A&M Mach 6 Quiet Tunnel
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Measurements of boundary layer transition location and boundary-layer profiles on a sharp-tipped 5°-half-angle flared cone were made in a low-disturbance Mach 6 wind tunnel. Following a recent nozzle repolishing effort, an updated flow quality characterization for the facility is presented for freestream unit Reynolds numbers of 8 and 10 × 106/m. At the high Reynolds number condition, transition onset on the flared cone model was observed to occur only very near its base, consistent with the previous observations on the same test article in the quiet tunnel's former installation at NASA Langley. Uncalibrated boundary-layer profiles of mean and rms mass flux are obtained using constant temperature hotwire anemometry at several axial locations, and are compared with available historical data. Locations of maximum fluctuating content within the boundary layer are consistent with previous experiments and expectation, although boundary-layer thicknesses are observed to be 16% higher than previously, most likely due to a slightly heated-wall condition on the cone. Several imminent improvements to the current hotwire technique are discussed. This early work represents a key milestone toward the acquisition of highly-resolved, calibrated measurements of hypersonic transitional boundary layers to be used as code validation. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.
author list (cited authors)
Hofferth, J., & Saric, W.