Computational analysis of the formation of Görtler vortices in the flow past a three-element airfoil

A high-order spectral element method is used to study the flow characteristics of a 30P30N three-element high lift wing at low Reynolds numbers. The primary focus is on investigating the flow structures within the slat cove and the formation of Görtler vortices on the upper surface of the main airfoil. By evaluating the spanwise velocity component within the slat cove, a distinct sinusoidal pattern with a fixed wavelength corresponding to that of the Görtler vortices is observed. The amplitude of the spanwise velocity exhibits an exponential growth before reaching a saturation state. Proper Orthogonal Decomposition (POD) analysis of the flow structures in the slat cove shows that the flow is initially characterized by shear layers, which subsequently evolve into spanwise perturbations. Especially, Görtler vortices are shown to arise from the separation flow of the trailing edge of the slat.