Large eddy simulations of MHD Turbulence

Abstract:

Increases in computer power, while important, are not likely to have a large impact on the problem of simulating turbulence at high Reynolds number. The energy and anisotropy are contained predominantly in the larger scales of motion, but most of the computational effort in a direct numerical simulation (DNS) is expended on the smallest dissipative motions. We present preliminary results from a large eddy simulation (LES) with periodic cubic geometry, where we do not attempt to simulate all the wavenumber modes up to the viscous cut-off. Only the large scales are explicitly resolved, while the interaction of the large scales with the smaller scales is modeled. The model is localized by dynamical calculation of the closure parameters. The performance of different models is evaluated by comparison of LES results with data from a higher resolution DNS. We intend this study to form a basis for the implementation of the large eddy simulation technique in a global simulation of the solar wind.