The propeller-induced ground vortex phenomenon is investigated by a propeller model at headwind highly loaded conditions. Large Eddy Simulation (LES) calculations are performed on a simplified model of the experimental, fixed ground conditions and validated against the experimental result. The computations are subsequently applied to the take-off configuration with a moving ground. The experimental and numerical results show that a system of vortices generated near the ground ascends to the propeller. The strength of the ground vortices is dependent on the thrust coefficient: as the propeller thrust coefficient is increased, the amount of vorticity produced near the ground grows. The quality of the flow entering the propeller plane is affected by the ground vortices. This is quantified in terms of a blade load non-uniformity coefficient (BLN), which is shown to increase as the thrust coefficient is increased. The topology of the ground vortices at take-off condition with the moving ground is the same as that at experimental headwind condition, but the meandering area of vortices moves further downstream than for the fixed ground. The strength of ground vortices at take-off condition is lower than that at headwind condition; accordingly the impact of vortices on the propeller inflow is weaker.
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