Application of Near-wall Models Along with LES to Free Surface and Separated Flows

Document Type : Research Article

Authors

Abstract

Application of Near-wall models along with large eddy simulation method for free-surface flow over
backward-facing step is investigated. Smagorinsky and Dynamic sub-grid scale models are used in
LES code. Four different near-wall models have been developed based on advanced Werner-Wengle
model. The simulation results are compared with experimental data of Nakagawa and Nezu (1987).
The comparison shows a relatively good agreement for time-averaged velocities and also it shows
high accuracy in computation of reattachment point. Near-wall models have very close results in
whole domain except the reattachment region and this has been shown by comparison of viscose sublayer
thickness that is an important parameter of these models. Although the dynamic sub-grid scale
model is more complicated than standard model, both models have shown very close results in present
case study.