Turbulence Modeling Challenges in Airship

Turbulent separated flows around an airship-like geometry (a prolate spheroid 6:1) are investigated using three turbulence modelings based on statistical and Large Eddy Simulation (LES) approaches. The turbulence models used in the simulations are a standard high Reynolds k–ε model, a Smagorinsky LES model and a variational multiscale LES one. The flow of interest is characterized by a relatively low Mach number (Mach = 0.15), an angle of attack set to 20◦ and a Reynolds number fixed to 4 × 104. The threedimensional compressible Navier-Stokes equations equipped with the previous turbulent models are discretized by a mixed finite element/finite volume method. The simulations show that the primary longitudinal vortex is predicted by the three models, but only the VMS-LES model predicts a secondary vortical flow structure that is observed in experimental studies.