Towards lagrangian large vortex simulation

Department of Mechanical Engineering The Johns Hopkins University Baltimore, MD 21218, USA

Abstract

Construction of a Lagrangian large-eddy-simulation scheme is performed based on filtering the vorticity transport equation and using simple eddy-diffusivity models to account for subgrid-scale "Helmholtz" stresses. The resulting governing equations are simulated using a three-dimensional particle method which discretizes the vorticity field into Lagrangian vortex elements of finite overlapping cores. Vortex elements are transported along particle trajectories, while their vorticities evolve according to stretching and tilting by the resolved scales, molecular diffusion, and subgrid-scale stresses. The behavior of the model is discussed in light of limited three-dimensional computations of transitional vortex rings. It is shown that the model can capture the large-scale features of the flow without requiring an excessively large number of elements.