A Physics-Based Investigation of Gurney Flaps for Rotor Vibration Reduction

A dynamically deployed Gurney flap was examined as a vibration reduction mechanism. A Navier- Stokes/Free wake hybrid method was used for a physics-based investigation of the Gurney flap effect. A previously trimmed prescribed motion was used for a quick examination of this concept. The 4-perrevolution normal force at the hub was compared with the loads for a higher harmonic controlled rotor and the baseline rotor. The simulation showed that the proper Gurney flap deployment reduced 80% of the 4P normal force vibration, whereas the higher harmonic controlled rotor reduced 53%. With proper on-board controller, further reduction of the vibration is expected with the Gurney flap. However, the Gurney flap caused blade sectional nose-down pitching moment and altered the trim condition. Thus, additional CFDCSD coupling analysis for aeroelastic deformation and rotor trim is required.