RANS and detached-eddy simulation of the NCCR airfoil

A circulation control foil is studied using incompressible Reynolds-averaged Navier Stokes and detached-eddy simulation CFD methods. It is shown that Reynolds-averaged Navier-Stokes simulations of large jet momentum coefficient cases with a linear Reynolds-stress closure and a blended k-ω = k-ε turbulence model is able to successfully predict the pressure-distribution trends in comparison to benchmark data. Details of the simulated flow are presented through analysis of the integral forces and moment, velocity field, and turbulent kinetic energy. However, given the lack of data and CFD grid studies these results lack validation. Detached-eddy simulation is undertaken for the unblown case, and demonstrates that the method is capable of resolving turbulent vortex shedding. Statistical and spectral analysis is used to explain the simulation results, however, as with the RANS simulations, lack of data precludes validation for this problem. Nonetheless, results are encouraging and suggest further application of DES to both circulation control studies as well as other trailing-edge applications. Finally, implications for cavitation-free operation of circulation-control devices are discussed.