Some properties of a class of large eddy simulation turbulence models for incompressible magnetohydrodynamics

 A new class of large eddy simulation turbulence models for incompressible magnetohydroynamics was developed in [1]. The new models were based upon the residual-based variational multiscale formulation. Tests on the decaying Taylor-Green vortex flow at various Reynolds numbers showed good results when compared to direct numerical simulations. The residual-based character of the models allows them to adapt to the flow physics. Moreover, the models are insensitive to model parameters. This property is demonstrated on three TG vortex flows each exhibiting a different energy spectrum. The new models, without any parameter tuning, are able to capture the correct inertial range behavior of each flow. Such adaptivity may be beneficial given the non-universality of MHD turbulence. Finally, under certain flow conditions, the models are able to capture a subgrid dynamo phenomenon in which an inverse energy cascade from unresolved velocity scales transfers energy to the resolved magnetic field.

[1] Sondak, D., Shadid, J.N., Oberai, A., Pawlowski, P., Cyr, E.C., Smith, T.M., A new class of finite element variational multiscale turbulence models for incompressible magnetohydrodynamics, Journal of Computational Physics 295, 596-616, 2015.