TY - JOUR
T1 - Microramp flow control of normal shock/boundary-layer interactions
AU - Herges, Thomas
AU - Kroeker, Erik
AU - Elliott, Greg
AU - Dutton, Craig
N1 - Funding Information:
The authors would like to thank Rolls–Royce, plc., and Gulfstream for funding this work on small-scale two-dimensional microramp effects. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of Rolls–Royce, plc., and Gulfstream. Additionally, we would like to thank our colleagues, Eric Loth at the University of Illinois, Tim Conners, Robbie Cowart, and Tom Wayman at Gulfstream, and Rod Chima, Jim Debonis, and Stefanie Hirt at NASA for their discussions and input regarding this work.
PY - 2010/11
Y1 - 2010/11
N2 - Boundary-layer bleed has conventionally been used to control separation due to shock wave/boundary-layer interactions within supersonic engine inlets. However, bleed systems result in a loss of captured mass flow, incurring higher drag and, ultimately, lower propulsion system efficiency. Microramp sub-boundary-layer vortex generators arranged in a spanwise array have been proposed in the past as a form of flow-control methodology for shock wave/ boundary-layer interactions. Experiments have been conducted herein at Mach 1.4 to characterize flow details of such devices and obtain quantitative measurements of their ability to control the interaction of a normal shock with a turbulent boundary layer. The flowfield was analyzed using schlieren photography, surface oil flow visualization, pressure-sensitive paint, and particle image velocimetry. An array of three microramps, for which the height was scaled to 36% of the incoming boundary-layer thickness, was placed ahead of the normal shock interaction. It was demonstrated that the microramps did entrain higher-momentum fluid into the boundary layer, which improved boundary-layer health. Specifically, the incompressible displacement thickness, momentum thickness, and shape factor were decreased, and the skin friction coefficient was increased, for the shock wave/boundary-layer interaction with the microramp array relative to the no-array case.
AB - Boundary-layer bleed has conventionally been used to control separation due to shock wave/boundary-layer interactions within supersonic engine inlets. However, bleed systems result in a loss of captured mass flow, incurring higher drag and, ultimately, lower propulsion system efficiency. Microramp sub-boundary-layer vortex generators arranged in a spanwise array have been proposed in the past as a form of flow-control methodology for shock wave/ boundary-layer interactions. Experiments have been conducted herein at Mach 1.4 to characterize flow details of such devices and obtain quantitative measurements of their ability to control the interaction of a normal shock with a turbulent boundary layer. The flowfield was analyzed using schlieren photography, surface oil flow visualization, pressure-sensitive paint, and particle image velocimetry. An array of three microramps, for which the height was scaled to 36% of the incoming boundary-layer thickness, was placed ahead of the normal shock interaction. It was demonstrated that the microramps did entrain higher-momentum fluid into the boundary layer, which improved boundary-layer health. Specifically, the incompressible displacement thickness, momentum thickness, and shape factor were decreased, and the skin friction coefficient was increased, for the shock wave/boundary-layer interaction with the microramp array relative to the no-array case.
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U2 - 10.2514/1.J050313
DO - 10.2514/1.J050313
M3 - Article
AN - SCOPUS:78650402536
SN - 0001-1452
VL - 48
SP - 2529
EP - 2542
JO - AIAA journal
JF - AIAA journal
IS - 11
ER -