An investigation of an implicit large-eddy simulation framework for the vorticity transport equations
Abstract
Complex vortex-dominated turbulent flows are prominent in a wide range of applications. In particular, we identify turbulent wakes with large coherent vortical structures such as those prevalent in rotor craft and wind turbine wakes as flow fields where conventional velocity-pressure formulation of the Navier-Stokes equations can become computational expensive in order to produce sufficiently resolved flow fields that maintain vortical structure coherence. An alternative is to reformulate the problem into vorticity and velocity variables and solve the incompressible vorticity transport equations. In this work, we investigate an upwind generalized Riemann problem-based multi-dimensional finite volume scheme to establish its capablili-ties within the philosophy of implicit large-eddy simulation (iLES). Modified equation analysis of two limiting cases reveals that high numerical diffusion can be realized in under-resolved regions and that low numerical diffusion can be obtained in well resolved regimes. Both limits are vital to employing iLES in vortex-dominated flows. Numerical experimentation employing simulations of the Taylor-Green vortex and isotropic turbulence is performed. The results with the implicit sub-grid scale model show that characteristics in terms of dissipation, turbulence spectra and turbulence statistics are captured reasonably well. The experimentation reveals that under-resolved simulations with the present scheme perform reasonably well when the inertial range is relatively large and the dissipative scales do not affect the energy-containing scales. We characterize the flow in terms of an effective Reynolds number, highly dependent on resolution, which allows for the prediction of the flow field quantities. Examples show that this framework can be applied to practical problems with complex turbulent flow fields.
Publication Title
2018 Fluid Dynamics Conference
Recommended Citation
Foti, D., & Duraisamy, K. (2018). An investigation of an implicit large-eddy simulation framework for the vorticity transport equations. 2018 Fluid Dynamics Conference https://doi.org/10.2514/6.2018-3407
