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RAPIDLY SHEARED HOMOGENEOUS MHD TURBULENCE IN A ROTATING FRAME

Evangelos E. Akylas
Department of Civil Engineering and Geomatics, Cyprus University of Technology, P.O. Box 50329, 3603, Limassol, Cyprus

Stavros C. Kassinos
Department of Mechanical Engineering Stanford University Stanford, California 94305 USA; Department of Mechanical and Manufacturing Engineering, Computational Sciences Laboratory, UCY-COMPSCI University of Cyprus, Nicosia, Cyprus

Elias Gravanis
Department of Civil Engineering and Geomatics Cyprus University of Technology, Limassol, Cyprus

要約

Rapid distortion theory is applied to magneto-hydrodynamic turbulence that is sheared in a rotating frame. We describe analytically the modification of the three-dimensional velocity spectra due to the presence of an external magnetic field, using the quasi-static approximation. Using this analytical solution, we investigate the effect of the frame rotation in the evolution of one-point statistics, under the linear theory. For initial fields that are two-dimensional (but three-componential), with the axis of independence aligned with the flow direction, we derive analytically one-point statistics, such as the Reynolds stresses and the structure dimensionality tensor in physical space. The analytical results are compared with the linear three-dimensional exact numerical solution for initially isotropic homogeneous turbulence, and they show remarkable agreement. They describe accurately the tendencies in the morphology of the turbulent structures that develop as a result of the two competitive mechanisms of the frame rotation and the Joule dissipation. These results are in qualitative agreement with existing non-linear DNS results.