Wind Tunnel Assessment of the Computational Framework for Helicopter Fuselage Drag Reduction Using Vortex Generators

A comprehensive wind tunnel campaign was performed to assess the results of a computational framework aimed to study the optimal layout and position of vortex generators for helicopter fuselage drag reduction. The most promising vortex generators configurations indicated by the numerical study were tested on a heavy-class helicopter fuselage model. The experimental activity, including loads, pressure measurements and stereo particle image velocimetry surveys, confirmed the main trends predicted by numerical simulations. In particular, the wind tunnel tests results showed that the best array of vortex generators positioned on the model back-ramp downstream the fuselage upsweep produces a maximum drag reduction of about 5% with respect to the measured clean fuselage drag. Moreover, velocity fields and pressure distributions evaluated around the backdoor/tail-boom junction enabled to investigate the flow physics related to the vortex generators functioning for fuselage drag reduction.