On the effect of airfoil geometry on extreme vortex-gust encounters

Historically, investigations on gust encounters have been limited to thin airfoils. In this work, we examine vortex-gust encounters by a family of airfoils at a chord-based Reynolds number italic Re Subscript c Baseline equals 100 Re c = 100 ${\textit{Re}}_c=100$ , which includes variations in the gust ratio, initial gust position, gust radius, angle of attack, airfoil thickness and airfoil camber. We examine differences in the flow fields, lift-element distributions and aerodynamic responses across several airfoil–gust interactions. We observe a large deviation of the flow fields and aerodynamic responses with respect to the baseline flows for increasing gust ratios and gust sizes. The initial position of the vortex gust influences the magnitude of the velocity gradients observed near the leading edge, effectively heightening or mitigating the amplitude of the lift response. Moreover, the lift fluctuation increases with the angle of attack until it flattens around 10 Superscript ring 10 ∘ $10^\circ$ , reminiscent of an unsteady stall-like regime. Furthermore, we report a decrease in the amplitude of the gust-induced lift fluctuations for thicker airfoils, which we attribute to a decrease in the vorticity production levels from the leading edge, as well as a spatial redirection of the transient aerodynamic forces, which shifts the response in favour of drag fluctuations. The exploration of a sensitive subset of the parameter space uncovers relevant trends, shedding light on regions that have received limited attention in past studies, with special focus on the influence of airfoil geometry.