Performance Enhancement in Dynamic Stall Condition Using Active Camber Deformation

This paper explores the possibility of using camber actuation as ameans for reducing vibration and improving performance in a rotor in the presence of dynamic stall. For the analysis of a rotor bladewith camber actuation in forward flight conditions, a modified version of the ONERA dynamic stall model was included in the analysis code UM/NLABS-A (University of Michigan, Nonlinear Asymptotic Beam Solver coupled with Aerodynamics). In the optimization, the amplitude and phase of camber actuation at 2/rev, 3/rev, 4/rev, and 5/rev actuation frequencies were used as the design variables and the analysis was performed with both cubic and quadratic camber deformation shape functions. The optimization studies were performed using surrogate models in combination with the efficient global optimization algorithm. Using the scaled BO105 rotor as the baseline model, optimization results obtained showed 50% reduction in 4/rev vibratory loads at the hub and more than 3.5% improvement in the performance using camber actuation at an advance ratio of 0.33.