Large Eddy Simulation of Airfoil Self-Noise
Speaker: Joseph George Kocheemoolayil, Ph.D. Candidate, Stanford University
Presentation
Abstract
Over the past 15 years, significant strides have been made towards using large eddy simulations (LES) for predicting airfoil self-noise. However, they have largely been restricted to canonical configurations at low Reynolds numbers. We summarize the progress made towards extending the scope of LES-based predictions to full-scale Reynolds numbers and non-canonical configurations such as noise generated by flow past an airfoil in the near-stall and post-stall regimes.
The trailing edge noise section of the Benchmark Problems for Airframe Noise Computations (BANC) workshop features five canonical problems at full-scale Reynolds numbers. No first-principles based approach free of empiricism and tunable coefficients has successfully predicted trailing edge noise for the five configurations to date. Our simulations that combine LES with a model for unresolved near-wall turbulence predict trailing edge noise accurately for all five configurations. Successful prediction of noise generated by an airfoil in the near-stall regime will also be demonstrated.
Predicting the flow past a wind turbine airfoil in the post-stall regime is a formidable challenge in itself. A novel, large-span calculation that predicts the flow past a wind turbine airfoil in deep stall with unprecedented accuracy is presented. In agreement with a recent theoretical study, our simulation results indicate that the lower lift due to large-scale three dimensionality can be reproduced even in span-periodic calculations as long as the domain size is large enough to contain the stall cells.
Biography
Joseph George Kocheemoolayil is a Ph. D. candidate in the Department of Aeronautics and Astronautics at Stanford University. His current research focuses on large eddy simulation of airfoil self-noise. Prior to joining Stanford, Joseph received his Bachelor of Technology and Master of Technology degrees in Aerospace Engineering from Indian Institute of Technology Madras. He has worked at Sandia National Laboratories, Idea Research and Indian Institute of Science in the past. His broader research interests include aeroacoustics, thermoacoustic instabilities and large eddy simulation of turbulent flows.