Numerical study of round jet impingement in proximity of ground and a water surface

The goal of this paper is to study the difference in aerodynamics and flow physics of an air jet impinging on a solid ground and a water surface at low subsonic Mach numbers with different heights above the ground. Single air jet impingement on solid ground and water surface with baffle plate around the jet exit is simulated by employing the incompressible Reynolds-Averaged Navier-Stokes equations with k-ε turbulence model, and Volume of Fluid (VOF) tracking method for air/water interface. The simulation results show that at the same (small) impingement height, there is increase in lift force on the baffle plate due to impingement on the water surface which is contrary to the lift loss experienced in the presence of solid ground. Furthermore, in case of impingement on water surface, the simulation results at the same velocity but at different heights above the water surface show that the lift increase at lower height tends to become smaller as the height above the water surface increases finally showing a loss in lift as the jet exit moves from small distance to very large distance.