Inlet conditions for large eddy simulation: A review

The treatment of inlet conditions for LES is a complex problem, but of extreme importance as, in many cases, the fluid behaviour within the domain is determined in large part by the inlet behaviour. The reason why it is so difficult to formulate inlet conditions is because the inlet flow must include a stochastically-varying component: ideally this component should ‘look’ like turbulence whilst at the same time be as simple as possible to implement and modify. We review methods for accomplishing this reported in the literature, these being ‘precursor simulation’ methods and ‘synthesis’ methods, and implement our own novel versions of these using the code OpenFOAM. Conclusions have been drawn about the relative merits of the different approaches, based on the physical realism of the results and the ease of construction and use.