Inﬂuence of the turbulence representation at the inlet on the downstream ﬂow pattern in LES of backward-facing step
The impact of the choice of inlet boundary condition treatment on the ﬂuid ﬂow is studied in this work. The correct representation of the turbulence at the inlet to the domain is essential for the accuracy of Large Eddy Simulation. The inappropriate speciﬁcation of the inlet velocity has signiﬁcant effect on the downstream ﬂow pattern. The case of backward-facing step was used as a test case. Three different approaches of the inlet boundary conditions were studied: uniform velocity proﬁle, mean velocity proﬁle of the fully developed channel ﬂow and velocity obtained from mapping velocity from plane positioned behind the inlet back to the inlet. The results of the simulations were compared with experimental results. It has shown, that using uniform velocity proﬁle on inlet and even prescribing turbulent mean velocity proﬁle without proper representation of turbulence ﬂuctuations leads to unrealistic results.
© Owned by the authors, published by EDP Sciences, 2012