Numerical simulations are performed to investigate Reynolds-number effects on the complex surface flow around the A-airfoil at moderate-to-high Reynolds numbers. An anisotropic shear stress transport transition model is incorporated into a new hybrid Reynolds-averaged Navier–Stokes and large eddy simulation (LES) framework to improve predictions of laminar–turbulent transition and strongly anisotropic flows. The model demonstrates high accuracy against experimental data and produces results comparable to LES with substantially fewer grid requirements. The flow around the A-airfoil is investigated at two Reynolds numbers using this method. The results indicate that, at the higher Reynolds number, the suction-side boundary layer is thinner, the transition location moves upstream with reduced intensity, and trailing-edge separation is delayed, whereas at the lower Reynolds number, the lift-to-drag ratio decreases markedly, resulting in degraded aerodynamic performance. Anisotropy invariant maps reveal strong regional dependence of Reynolds-number effects on surface flow structures, mainly in the transition and recirculation regions. The mean power spectral density of surface pressure fluctuations further shows that Reynolds number strongly influences the frequency-domain energy distribution, with the largest differences appearing in the transition region.
Li et al. (Fri,) studied this question.