Analysis of intermittent vortex pairing for a transitional flow past a NACA0012 airfoil via a multidimensional empirical mode decomposition

Author(s)

Feitosa, Lucas ; Miotto, Renato ; Wolf, William

• Document type: Journal article
• Source: AIAA AVIATION FORUM AND ASCEND 2024; v. N/A, p. 9-pg., 2024-01-01.

Abstract

Modal decomposition techniques are crucial for identifying coherent structures in unsteady flows and revealing their characteristic frequencies, aiding in the development of effective control strategies. However, challenges arise when applying these techniques to transient and intermittent flows. In this paper, we explore the potential of the Fast and Adaptive Multivariate Empirical Mode Decomposition (FA-MVEMD) in capturing physically interpretable modes in intermittent flows. We apply the FA-MVEMD to a wall-resolved large eddy simulation dataset of a flow past a NACA0012 airfoil, where intermittent vortex pairing occurs due to Kelvin-Helmholtz instabilities downstream of a flapping separation bubble. We show how the FA-MVEMD, coupled with a Hilbert spectral analysis, elucidates the physics behind successful and unsuccessful vortex pairing events. Our results provide detailed insights into the convective stage of vortex merging and highlight the efficacy of the present multidimensional empirical mode decomposition (EMD) in analyzing intermittent flows. (AU)

• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 22/09196-4 - Improving the understanding of unsteady aerodynamic flows via high-fidelity simulations, analytical modeling and deep learning techniques
• Grantee: Renato Fuzaro Miotto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/06448-0 - High-fidelity numerical simulations applied in unsteady aerodynamics, turbulence and aeroacoustics
• Grantee: William Roberto Wolf
• Support Opportunities: Research Grants - Young Investigators Grants - Phase 2
• FAPESP's process: 22/08567-9 - Numerical investigation of an airfoil under light dynamic stall
• Grantee: Lucas Feitosa de Souza
• Support Opportunities: Scholarships in Brazil - Master