Low-Order Blade Modeling for Compressor Aeroelastics

Abstract : To incorporate blade-row unsteady aerodynamics into system-level flutter and forced response models, a frequency domain Proper Orthogonal Decomposition was applied to an Euler CFD code which incorporates motion of an unstructured grid. With Arnoldi vectors as input-output generalizations of the basis functions, an efficient moc order reduction procedure is developed and applied to a typical transonic rotor. These results helped incoporate model-order reduction procedures into the aeroelastic design and analysis procedures of Pratt & Whitney. In the second part of this effort low-order compressor models, are used to design static nonlinear controllers to suppress rotating stall, and thus extend the stable operating range of the compressor. New nonlinear controllers may introduce beneficial bifurcations and create the possibility of stabilizing optimal operating regimes with reduced control effort.