Nonlinear Development and Secondary Instability of Traveling Crossflow Vortices
Transition research under NASA's Aeronautical Sciences Project seeks to develop a validated set of variable fidelity prediction tools with known strengths and limitations, so as to enable "sufficiently" accurate transition prediction and practical transition control for future vehicle concepts. This paper builds upon prior effort targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration relevant to subsonic aircraft with laminar flow technology. Specifically, transition via secondary instability of traveling crossflow modes is investigated as an alternate scenario for transition. Results show that, for the parameter range investigated herein, secondary instability of traveling crossflow modes becomes insignificant in relation to the secondary instability of the stationary modes when the relative initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by more than one order of magnitude. Linear growth predictions based on the secondary instability theory are found to agree well with those based on PSE and DNS, with the most significant discrepancies being limited to spatial regions of relatively weak secondary growth, i.e., regions where the primary disturbance amplitudes are smaller in comparison to its peak amplitude. Nonlinear effects on secondary instability evolution is also investigated and found to be initially stabilizing, prior to breakdown.
F. Li et al., "Nonlinear Development and Secondary Instability of Traveling Crossflow Vortices," Proceedings of the 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014 (2014, National Harbor, MD), American Institute of Aeronautics and Astronautics (AIAA), Jan 2014.
52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014 (2014: Jan. 13-17, National Harbor, MD)
Mechanical and Aerospace Engineering
Center for High Performance Computing Research
Keywords and Phrases
Aerospace Engineering; Laminar Flow; NASA; Swept Wings; Breakdown Mechanism; Cross-Flow Instabilities; Crossflow Vortices; Disturbance Amplitudes; Secondary Instability; Subsonic Aircraft; Transition Control; Transition Prediction; Stability
International Standard Book Number (ISBN)
Article - Conference proceedings
© 2014 American Institute of Aeronautics and Astronautics (AIAA), All rights reserved.
01 Jan 2014