Pattern recognition of the flow around a pitching NACA 0012 airfoil in dynamic stall conditions

Pattern recognition of the flow around a pitching NACA 0012 airfoil in dynamic stall conditions

Giacomo Baldan, Alberto Guardone

Abstract. The present work numerically investigates the flow evolution of a pitching NACA 0012 airfoil incurring in deep dynamic stall phenomena. The experimental data at Reynolds number Re = 1.35 · 105 and reduced frequency k = 0.1, provided by Lee et al., are compared to numerical simulation using different methods. Firstly, 2D URANS with different turbulence models are explored highlighting the advantages and the drawbacks of each strategy. On the one hand, simulations are able to describe most characteristic flow features of dynamic stall. On the other hand, numerical models still struggle in describing the inherent complexity of instability and transition from laminar to turbulence, resulting in a misprediction of the angle of attack at which the dynamic stall vortex (DSV) is generated and convected rearward. Finally, a Proper Orthogonal Decomposition (POD) is proposed to analyze the main flow features and to recognize flow patterns. The decomposition of both velocity magnitude and pressure fields shows a high frequency content requiring a large portion of the modes to recover most of the flow energy.

Keywords
Dynamic Stall, Proper Orthogonal Decomposition, Pitching Airfoil, Pattern Recognition, Helicopters, Wind Turbines

Published online 11/1/2023, 5 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: Giacomo Baldan, Alberto Guardone, Pattern recognition of the flow around a pitching NACA 0012 airfoil in dynamic stall conditions, Materials Research Proceedings, Vol. 37, pp 161-165, 2023

DOI: https://doi.org/10.21741/9781644902813-35

The article was published as article 35 of the book Aeronautics and Astronautics

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

References
[1] M. Visbal, D. Garmann, “Analysis of Dynamic Stall on a Pitching Airfoil Using High-Fidelity Large-Eddy Simulations”. AIAA Journal 2018; 56(1):46-63. https://doi.org/10.2514/1.J056108
[2] F. Avanzi, F. de Vanna, Y. Ruan and E. Benini, “Enhanced Identification of Coherent Structures in the Flow Evolution of a Pitching Wing”. AIAA 2022-0182. AIAA SCITECH 2022 Forum. https://doi.org/10.2514/6.2022-0182
[3] A. D. Gardner, A. R. Jones, K. Mulleners, J. W. Naughton, M. J. Smith. “Review of rotating wing dynamic stall: Experiments and flow control”. Progress in Aerospace Sciences 2023; 137:100887. https://doi.org/10.1016/j.paerosci.2023.100887
[4] T. Lee, P. Gerontakos, “Investigation of flow over an oscillating airfoil”. Journal of Fluid Mechanics 2004; 512:313–341. https://doi.org/10.1017/S0022112004009851
[5] H. Eivazi, S. Le Clainche, S. Hoyas, R. Vinuesa. “Towards extraction of orthogonal and parsimonious non-linear modes from turbulent flows”. Expert Systems with Applications 2022; 202:117038. https://doi.org/10.1016/j.eswa.2022.117038