A-priori studies of a near-wall RANS model within a hybrid LES/RANS scheme

Achieving an acceptably accurate representation of the near-wall layer in LES for high-Re flows that are sensitive to viscous near-wall processes is one of the major challenges facing LES. Based on the premise that this can be addressed, in principle, by coupling a RANS near-wall model to the LES domain, the behaviour of a one-equation, turbulence-energy-transport model is examined in fully-developed channel flow. Initially, the response of the model is considered when this is subjected to the LES solution at a prescribed distance from the wall (y(+)=65). Coupling criteria are then discussed, given the desirability of freedom of choice of the subgrid-scale model in the LES domain and in locating the interface. Initial efforts towards a fully-coupled hybrid solution are also presented.