Advanced search
Start date
Betweenand


Adverse-pressure-gradient effects on extreme events and intermittency in the turbulent boundary layer of a NACA0012 at 12° angle of attack

Full text
Author(s):
de O Silva, Leandro Juni ; Wolf, William R. ; Vinuesa, Ricardo
Total Authors: 3
Document type: Journal article
Source: AIAA AVIATION FORUM AND ASCEND 2024; v. N/A, p. 13-pg., 2024-01-01.
Abstract

We investigate the effects of adverse pressure gradients (APGs) on extreme and intermittent events in the turbulent boundary layer (TBL) of a NACA0012 airfoil at 12 deg. angle of attack. A wall-resolved large-eddy simulation (LES) is performed for a Reynolds number Re = 4 x 10(5) and freestream Mach number M = 0.2. Boundary-layer tripping is enforced near the leading edge to produce bypass transition. Despite the high angle of attack, the mean flow remains attached throughout the airfoil suction side, although the adverse pressure gradient exhibits a steep rise towards the trailing edge. Results of a quadrant analysis for the Reynolds shear-stress distribution show that sweeps are predominant near the wall, while ejections dominate in the outer region. The former are the main contributor to the inner peak of turbulence production. Due to the strong APG, a secondary peak of production arises in the outer layer, and the combination of both sweeps and ejections contribute to such peak. A backflow characterization is performed, demonstrating that as the APG increases, the magnitude of the friction coefficient decreases, leading to a higher probability of such events near the trailing edge. (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: 22/00256-4 - Statistics of turbulent boundary layers developing under different pressure gradients
Grantee:Leandro Júnio de Oliveira Silva
Support Opportunities: Scholarships in Brazil - Master
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: 23/01657-5 - Study of adverse pressure gradient effects in turbulent boundary layers
Grantee:Leandro Júnio de Oliveira Silva
Support Opportunities: Scholarships abroad - Research Internship - Master's degree