Large-Eddy Simulation Studies of Bypass Transition

Abstract A large-eddy simulation has been performed of a boundary layer undergoing transition to turbulence owing to the presence of free-stream turbulence. The properties of the simulated transitional boundary layer are very similar to those found experimentally. Damping factors for popular closure models used to predict transition have been extracted from the large-eddy simulation, and are compared with three closure approximations, showing that all models overestimate the damping close to the wall. The results of numerical experiments (in the form of coarse simulations) are also reported, indicating the roles of the three perpendicular components of free-stream turbulence intensity, and of pressure fluctuations, in provoking bypass transition.