Prediction of Dynamic Stall Characteristics Using Advanced Nonlinear Panel Methods,
ANALYTICAL METHODS INC REDMOND WA
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This paper presents preliminary results of work in which a surface singularity panel method is being extended for modelling the dynamic interaction between a separated wake and a surface undergoing an unsteady motion. The method combines the capabilities of an unsteady time-stepping code and a technique for modelling extensive separation using free vortex sheets. Routines are developed for treating the dynamic interaction between the separated wake and the solid boundary in an environment where the separation point is moving with time. The behavior of these routines is examined in a parallel effort using a two-dimensional pilot version of the three-dimensional code. This allows refinements in the procedures to be quickly developed and tested prior to installation into the main code. The extended code is coupled with an unsteady integral boundary layer method to examine the prediction of dynamic stall characteristics. The boundary layer code is accessed during the timestep cycle and provides the separation locations as well as the boundary layer displacement effect -- the latter is modelled in the potential flow code using the source transpiration technique.