Numerical Investigations of Turbulent Inflow Condition Generation for LES

Abstract

Imposing realistic inlet conditions for Direct and Large-Eddy Simulation of spatially developing flow is extremely challenging, and requires careful considerations, especially for fully turbulent conditions (1-8), and references therein. Indeed, the development of turbulent flow is highly dependent on the properties of the upstream conditions. A new strategy for specifying realistic turbulent inflow condition has been recently developed (9). This method consists in using an experimental, time-dependent, highly turbulent velocity field as the inflow condition for spatially developing LES. Such methodology is based on the implementation of an interface between an experimental measurement section and the computational inlet section. Experimental time history data are obtained at few selected reference locations with hot-wire probes. From these measurements, the instantaneous velocity field is reconstructed at each grid point of the inlet mesh and is then used as an inflow condition for the simulation. On top of generating realistic turbulent inflow condition for LES, the interest of this association is to propose a new structure education method for representing and analyzing the three-dimensional (3D) dynamical evolution of the large-scale structures of the flow (10). In this work, the experiment∕simulation association has been tested for a specific test case flow configuration: the incompressible plane mixing layer.