Coherent-vorticity-Preserving (CvP) Large-Eddy Simulations (LES) of Very-High-Reynolds-Number Vortex Dynamics
Abstract
The new Coherent-vorticity-Preserving (CvP) Large-Eddy Simulation (LES) technique introduced by Chapelier & Scalo AIAA 2017-4168 deactivates eddy viscosity in regions of coherent narrowband large-scale vorticity, while restoring it in the presence of locally fully developed broadband turbulence. The CvP methodology relies on the fast evaluation of the local state of spectral broadening based on the application of Kolmogorov s K41 Theory to the filtered enstrophy field. It is shown how the CvP approach significantly extends the range of Reynolds numbers attainable by standard LES approaches for the same computational cost, enabling high-fidelity simulations at very high Reynolds numbers. Three canonical flow problems in coherent vortex dynamics of interest to the Army will be tackled. First, the breakdown to turbulence of single and double helical vortices at very high circulation Reynolds numbers will be simulated (Task I), replicating published experimental measurements by Nemes et al. JFM 2015 and Quaranta et al. JFM 2015. The dependency of the onset of long-wave instability and mutual inductance on the relevant flow parameters will be investigated up to the highest attainable Reynolds number with the available computational resources. Second, the evolution of knotted vortices with high topological complexity (Task 2) will be simulated via CvP-LES by replicating the experiments by Kleckner and Irvine, Nature Physics 2013. The chaotic nature of the onset of turbulent bursting upon vortex-to-vortex reconnection will be characterized via a sensitivity study to both numerical and physical perturbations of the initial conditions, as well as grid resolution. Third, CvP-LES reproducing the Direct Numerical Simulation (DNS) by Hickey et al. JFM 2013 of planar splitter-plate wakes will be carried out (Task 3). CvP-LES at the higher Reynolds numbers will then be performed shedding light on the existence of a high?Reynolds-number asymptotic collapse of different self-similar states originating from different initial conditions (i.e. splitter-plate exit conditions). This project absract is publicly releasable.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 07, 2018
- Source ID
- W911NF1810045
Entities
People
- Carlo Scalo
Organizations
- Army Contracting Command
- United States Army
- University of Virginia