[GTP] GTP/HAO Joint Seminar - Friday, 25 July - 3:00 PM

[Bonnie Slagel]

GTP and HAO will be hosting a seminar on Friday, 24 July at 3PM in
CG1-2139. The speaker will be Arakel Petrosyan from the Russian Academy of
Sciences.

*Seminar Title:*  Developments in Large Eddy Simulations for Compressible
MHD Turbulence in Space Plasma

*Seminar Abstract:  *Large eddy simulation (LES) method is developed for
study of decaying and forced compressible magnetohydrodynamic turbulence.
The obtained results of numerical computations for large eddy simulation
are compared with the results of direct numerical simulation of
three-dimensional compressible magnetohydrodynamic turbulence under various
similarity parameters, namely, magnetic Reynolds numbers, hydrodynamic
Reynolds numbers and Mach numbers for polytropic case. The comparison of
five subgrid-scale closures of large eddy simulation for
magnetohydrodynamic case is made: the Smagorinsky model, the Kolmogorov
model, the cross-helicity model, the scale-similarity model and mixed
model. The comparison between large eddy simulation and direct numerical
simulation is carried out regarding the time evolution of kinetic and
magnetic energy, cross helicity, subgrid-scale and molecular dissipations
for kinetic and magnetic energy, turbulent intensities and quantities that
describe anisotropy of flow, that is, skewness and kurtosis of velocity and
magnetic field. It is shown that some proposed subgrid-scale models provide
sufficient dissipation of kinetic and magnetic energy, reduce computational
efforts and produce adequate results of magnetohydrodynamic turbulent
modeling for various values of similarity parameters of flows. We also
consider a heat conducting compressible fluid with the use of an energy
equation. Application of large eddy simulation approach to understand
observed density fluctuations spectra in local interstellar media is
reported. Novel developments in application of LES for forced compressible
MHD turbulence are discussed.


-- 
Bonnie Slagel
NCAR's Earth System Laboratory (NESL)
PO Box 3000
Boulder, CO  80307-3000
303-497-8318
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