Inlet Conditions for LES of Swirl Flows

In this paper we present a novel technique for generating swirl inlets for Large Eddy Simulation (LES). The velocity a short distance downstream of the inlet to the main domain is sampled and the flow velocity data reintroduced back into the domain inlet, creating an inlet section integrated into the main domain where turbulence can develop. Additionally, variable artificial body forces and velocity corrections are imposed in this inlet section, with feedback control to force the flow towards desired swirl, mean and turbulent profiles. The method has been applied to swirling flow in a circular pipe and in an axisymmetric sudden expansion, and for the latter case compared against experimental and literature LES data, and against similar results in the literature. The method generates excellent results, and is elegant and straightforward to implement.