City Research Online

Abstract

Large eddy simulations are conducted for a pitching National Advisory Committee for Aeronautics 63(3)418 airfoil section at a reduced frequency of K=0.4 and a chord-based Reynolds number, Rec=100 000. The goal of this work is to understand how transient stall flutter dynamics are affected by initial flow field conditions associated with a high incidence angle. Perturbation starting times are varied parametrically to investigate the differences in the transient dynamic stalling processes over a single pitching cycle. It is found that Kármán vortex shedding associated with an initially static airfoil interferes with the leading-edge vortex detachment and dynamic lift stall as per large variations in the post-stall unsteady aerodynamic loading. Monitored leading-edge vortex trajectories and computed Lagrangian averaged vorticity deviation fields both confirm this notion and are utilized to link this phenomenon to the status of a trailing-edge vortex. It is shown that the leading-edge vortex trajectory standard deviation leading up to dynamic lift stall contracts at a singular point in space. This event appears to be weakly connected to the leading-edge vortex circulation during its maturation stage. The leading-edge vortex morphology is also investigated near its detachment location through several morphometric quantifiers such as the area, aspect ratio, and eccentricity. It is found that the leading-edge vortex morphology undergoes a similar contraction in the aspect ratio and eccentricity standard deviations. Finally, near-surface measurements of the u and v signals grant an indirect quantification of the leading-edge vortex strength and position as it advects over the airfoil chord.

Publication Type:	Article
Additional Information:	© 2026 Author(s). Published under an exclusive license by AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Physics of Fluids, 38(1), article number 017139 and may be found at https://doi.org/10.1063/5.0310207
Publisher Keywords:	Wind energy, Aerodynamics, Applied fluid dynamics, Turbulence simulations, Vortex dynamics
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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