VpLES- Particle Intensified Large Eddy Simulation N. Kornev and S. Samarbakhsh VIII International Conference on Computational Methods in Marine Engineering MARINE 2019 R. Bensow and J. Ringsberg (Eds) VπLES- VORTEX PARTICLE INTENSIFIED LARGE EDDY SIMULATION S. Samarbakhsh ∗ and N. Kornev † Chair of modeling and simulation University of Rostock Rostock, Germany ∗ e-mail: sina.samarbakhsh@uni-rostock.de † e-mail: nikolai.kornev@uni-rostock.de Key words: LES, subgrid model, meshless method, free jet, hybrid Eulerian/Lagrangian method Abstract. This paper presents the progress in the development of a novel numerical technique which utilizes the combination of grid based and grid free computational methods. This novel Large Eddy Simulation approach with a direct resolution of the subgrid motion of fine concen- trated 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. Algorithmic aspects specific for three dimensional flow simulations are discussed. Validity and advantages of the new approach were illustrated for a well tried benchmark test of the decaying homogeneous isotropic turbulence and turbulent free jet flow. The aim of this paper is to present some new results on the possibility of the model reduction and explanation of the anisotropy of fine scale vortices. 1 INTRODUCTION Insufficient resolution of fine vortex structures in turbulent flows is one of the key problems in Computational Fluid Dynamics (CFD). The most advanced and popular technique to resolve multi scale flow structures is the Large Eddy Simulation (LES) which is based on the idea of scale decomposition into large and small ones. While the large eddies are directly resolved on the grid, the effect of small vortices is taken into account through a subgrid stress (SGS) model. The subgrid motion is not resolved in LES but rather it is modelled using different functional and structural approaches. However, there are many problems which require direct representa- tion of the subgrid motion to simulate, for instance, mixing or particle dynamics in turbulent 1 60