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NIA Seminar by Li Jiang |
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Date: August 1, 2006
Time: 10:30am
Location: NIA, Rm 137
Direct Numerical Simulations of Crossflow Disturbances in Supersonic Boundary Layers
Li Jiang, University of Texas, Arlington
Stringent requirements for component performance plus economic and environmental challenges for supersonic aircraft leave little room for inefficiencies in airframe design (NRC 2002), making it necessary to have accurate and reliable analysis tools for supersonic laminar flow control (SLFC). To help develop and calibrate physics-based prediction tools for boundary layer transition to turbulence, direct numerical simulations (DNS) of various stages of transition over model as well as realistic flow configurations are required. In this talk, the application of a DNS solver based on high-order compact differences to supersonic swept-wing and cone configurations will be presented. Specifically, spatial simulations of crossflow instability in swept-wing boundary layers have been performed and compared with predictions based on the simpler but almost equally accurate parabolized stability equations. The DNS results for nonlinear crossflow evolution are used to obtain further insights into the physics of roughness-based SLFC and, hence, to suggest potential ways of applying nonlinear prediction tools in a design setting. The excitation of stationary crossflow and Gortler modes due to localized surface disturbances is also investigated.
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