An experimental investigation of ground effect on rotorcraft in the presence of sidewall

Rotorcraft flying in close proximity to ground are known to generate a larger thrust due to the shed wake being obstructed by the ground. The effect has been well researched and empirical corrections are available in literature. However, studies on the influence of side walls on ground effect is still lacking. Such studies may be applied to full scale rotorcraft hovering near walls, skyscrapers and similar structures, rotor-based UAVs flying in a constrained space and in corrections for wall interference in wind tunnel testing. Analytical models are presently available for modelling the effect of wind tunnel wall interferences in specific wind tunnels, however they are rarely prescribed in a form applicable to generalized situations like a helicopter approaching a single side wall in ground effect. This work aims to study the influence of side walls in the presence of ground using experiments conducted on a model rotor. Force and Torque measurements are obtained using a six-Axis load cell.