Vortex particle intensified large eddy simulation - VπLES

Abstract

This paper presents a novel Large Eddy Simulation approach with a direct resolution of the subgrid motion of fine concentrated vortices. The method, proposed first by [10], is based on combination of a grid based and the grid free computational vortex particle (VPM) methods. The large scale flow structures are simulated on the grid whereas the concentrated structures are modeled using VPM. Due to this combination the advantages of both methods are strengthened whereas the disadvantages are diminished. The procedure of the separation of small concentrated vortices from the large scale ones is based on LES filtering idea. The flow dynamics is governed by two coupled transport equations taking two-way interaction between large and fine structures into account. The fine structures are mapped back to the grid if their size grows due to diffusion. Algorith- mic aspects specific for three dimensional flow simulations are discussed. Validity and advantages of the new approach are illustrated for a well tried benchmark test of the decaying homogeneous isotropic turbulence using the experimental data of [4] and free turbulent jet flow using experiments of [8, 2, 15].