Numerical investigation on the aerodynamic interference of water waves on an airfoil within ground effect

To reveal the characteristics of wave-induced aerodynamic interference on ground effect vehicles, the simulation of an airfoil flying over waves has been conducted within ground effect with the chord-based Reynolds number of 6.85 × 10 7 . Third-order Stokes waves and Airy waves are numerically generated using the Volume of Fluid (VOF) method combined with inflow boundary conditions. Comparative simulations are performed across the flat water and the third-order Stokes wavy wall. The propagating waves induce updrafts in the forward direction and downdrafts on the back side. The wave-induced updrafts and downdrafts cause fluctuations in the strength of the leading-edge suction peak and the pressure on the airfoil lower surface, thereby driving oscillations in the airfoil's aerodynamic forces. The nonlinearity in third-order Stokes water waves exhibits negligible effects on airfoil aerodynamics, with results closely approximating those predicted by linear wave theory. The aerodynamic forces obtained using a third-order Stokes wavy wall boundary significantly underestimates the fluctuation amplitudes compared to water wave conditions. A single-variable parametric study was conducted to quantify the effects of wave height, wavelength, and flight height on the aerodynamic characteristics of the airfoil. Within the investigated parameter ranges, reductions in wavelength, increases in wave height, and decreases in flight height each amplified the fluctuation amplitudes of the airfoil's lift and pitching moment.