Large eddy simulation of backward‐facing step flow

Recirculating flow around a backward‐facing step is calculated by large eddy simulation (LES). The reattachment length is found to be xR/H = 8 for a Smagorinsky constant of C =0.15, and xR/H = 9 for C =0.10. In the recirculating region, three eddy structures can be observed in the instantaneous streamline distributions, and the location of the reattachment point varies according to the size of these eddies. The stream‐wise turbulence intensities at the start of the recirculating region around the step are considerably reduced by LES in comparison with the values predicted by the k – ϵ model, but they have somewhat higher values than those of the k – ϵ model as it approaches the reattachment point.