Numerical Simulation of Dynamic Stall

The objective of the proposed program is to develop, demonstrate and validate a three-dimensional, time-dependent, compressible Navier-Stokes program for predicting dynamic stall. The foundation of the program is an existing 3-D program that has been developed under prior SBIR funding for retreating-blade dynamic stall on modern high-performance helicopter rotors. The program will be improved in four significant ways. First, capability for dynamic adaptive grid generation will be incorporated in the program. Second, an optimum second-order closure model will be selected for inclusion in the program. Third, a rational method will be devised to predict the onset of transition to turbulence, including initial conditions for a turbulence-model computation through transition and into the turbulent regime. The revised code will bed exercised (using its currently implemented two-equation turbulence model) for a two-dimensional geometry for both deep- and light-stall conditions. Fourth, advances in the solution algorithm will be incorporated, including nonlinear multigrid, TVD, higher-order advective differencing, and true periodicity across the c-c grid. The Phase II code will include the new transition/turbulence models and will be exercised for three-dimensional problems.