Kunihiko Taira
Mechanical and Aerospace Engineering, UCLA, USA
http://www.seas.ucla.edu/fluidflow/
Date(s) : 27/01/2021 iCal
14 h 00 min - 15 h 00 min
While the setup of a wing in freestream may appear simple, the flow generated in its wake exhibits remarkably rich dynamics. This is especially true for a finite-aspect-ratio wing at a post-stall angle of attack, which is often the wing of choice for birds, insects, and modern aircraft. The wing aspect ratio, angle of attack, sweep, Reynolds number, and Mach number (!) all uniquely contribute to the complex dynamics [1, 2, 3]. Although low-aspect-ratio wings are ever more prevalent in aeronautical designs, understanding of these flows is limited due to the vast parameter space. To gain fundamental insights into low-aspect-ratio wing flows at low Reynolds numbers, we computationally examine the importance of three-dimensional separation and wake behavior. Furthermore, a brief survey of our recent efforts to model and control these flows with modal analysis and data-driven techniques will be provided [4, 5, 6].
[1] K. Taira and T. Colonius, “Three-Dimensional Flows around Low-Aspect-Ratio Flat-Plate Wings at Low Reynolds Numbers,” Journal of Fluid Mechanics, 623, 187-207, 2009.
[2] K. Zhang, S. Hayostek, M. Amitay, W. He, V. Theofilis, and K. Taira, “On the Formation of Three-Dimensional Flows over Wings under Tip Effects,” Journal of Fluid Mechanics, 895, A9, 2020.
[3] K. Zhang, S. Hayostek, M. Amitay, A. Burtsev, V. Theofilis, and K. Taira, “Laminar Separated Flows over Finite-Aspect-Ratio Swept Wings,” Journal of Fluid Mechanics, 905, R1, 2020.
[4] A. M. Edstrand, Y. Sun, P. J. Schmid, K. Taira, and L. N. Cattafesta, “Active Attenuation of a Trailing Vortex Inspired by a Parabolized Stability Analysis,” Journal of Fluid Mechanics, 855, R2, 2018.
[5] K. Taira, M. S. Hemati, S. L. Brunton, Y. Sun, K. Duraisamy, S. Bagheri, S. T. M. Dawson, and C.-A. Yeh, “Modal Analysis of Fluid Flows: Applications and Outlook,” AIAA Journal, 58(3), 998-1022, 2020.
[6] A. G. Nair, C.-A. Yeh, E. Kaiser, B. R. Noack, S. L. Brunton, and K. Taira, “Cluster-Based Feedback Control of Turbulent Post-Stall Separated Flows,” Journal of Fluid Mechanics, 875, 345-375, 2019.
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