Technical Paper
Pressure Field Evolution on Rotor Blades at High Advance Ratio
2016-09-20
2016-01-2010
The design of advanced rotorcraft requires knowledge of the flowfield and loads on the rotor blade at extreme advance ratios (ratios of the forward flight speed to rotor tip speed). In this domain, strong vortices form below the rotor, and their evolution has a sharp influence on the aero-dynamics loads experienced by the rotor, particularly the loads experienced at pitch links. To understand the load distribution, the surface pressure distribution must be captured. This has posed a severe problem in wind tunnel experiments. In our experiments, a 2-bladed teetering rotor with collective and cyclic pitch controls is used in a low speed subsonic wind tunnel in reverse flow. Stereoscopic particle image velocimetry is used to measure the three component spatial velocity field. Measurement accuracy is now adequate for velocity data, and can be converted to pressure both at and away from the blade surface.
