Experimental Investigation of Active Aerodynamic Load Reduction on a Rotorcraft Fuselage with Rotor Effects

Abstract

The reduction of both the drag and the download that act on a generic rotorcraft fuselage by the application of active flow control was investigated in a wind tunnel test conducted on a 1/3-scale powered rotorcraft model. The fuselage, the ROBIN-mod7, was equipped with a series of eight slots located on the ramp section and arranged in a U-shaped pattern. This U-shaped pattern was located slightly downstream of the baseline separation line and parallel to it. The flow control excitation took the form of zero-net-mass-flow blowing, also called synthetic jets, and steady blowing. The same set of slots were used for both types of excitation. The effectiveness of the control over a wide range of model parameters (angle of attack, advance ratio, and thrust coefficient) was documented. Both types of control were able to successfully produce a significant drag and download reduction. For synthetic jet control acting at a low advance ratio, the maximum drag and download reduction was 22% and 43%, respectively. For the case of steady blowing applied at high advance ratio, the maximum drag and download reduction was 45% and 58%, respectively.