Scalable Aerodynamics and Coupled Comprehensive Module for the Prediction of Rotorcraft Maneuver Loads

Modern rotorcraft, when engaged in high speed or maneuvering flight, can experience very complex and highly non-linear aerodynamic phenomena that induce exceptionally high loads on the rotor system. Aerodynamic and structural interactions can lead toviolent vibrations, reduced handling qualities, and reduction in fatigue life. The principal mechanism of this behavior is dynamic stall, which involves a cyclic event of massive flow separation, the shedding and convection of a vortex over the bladesurface, and flow reattachment.Flow Analysis, Inc. (FAI) has developed a technique for predicting dynamic stall for airfoils, wings, and rotor blades that is based on the vorticity confinement method. The method allows vortex-dominated flows to be computed on coarse grids without thedissipation normally associated with conventional CFD approaches, thereby resulting in significant computational savings. Application to various airfoils and stall conditions has demonstrated the general applicability, accuracy, and robustness of themethod.We propose to combine in a parallel processing environment the FAI dynamic stall method (implemented in a compressible flow solver) with a comprehensive structural dynamics code. The result will be a unique and powerful approach to dynamic stall modelingthat will be the basis for a new comprehensive rotorcraft modeling system.