Magnetohydrodynamic lattice Boltzmann simulations of turbulence and rectangular jet flow

Show full item record

Title: Magnetohydrodynamic lattice Boltzmann simulations of turbulence and rectangular jet flow
Author: Riley, Benjamin Matthew
Abstract: Magnetohydrodynamic (MHD ) investigations of decaying isotropic turbulence and rectangular jets (RJ ) are carried out . A novel MHD lattice Boltzmann scheme that combines multiple relaxation time (MRT ) parameters for the velocity field with a single relaxation time (SRT ) parameter for the Maxwell ?s stress tensor is developed for this study . In the MHD homogeneous turbulence studies , the kinetic /magnetic energy and enstrophy decays , kinetic enstrophy evolution , and vorticity alignment with the strain -rate tensor are evaluated to assess the key physical MHD turbulence mechanisms . The magnetic and kinetic energies interact and exchange through the influence of the Lorentz force work . An initial random fluctuating magnetic field increases the vortex stretching and forward cascade mechanisms . A strong uniform mean magnetic field increases the anisotropy of the turbulent flow field and causes inverse cascading . In the RJ studies , an investigation into the MHD effects on velocity , instability , and the axis -switching phenomena is performed at various magnetic field strengths and Magnetic Reynolds Numbers . The magnetic field is found to decelerate the jet core , inhibit instability , and prevent axis -switching . The key physical mechanisms are : (i ) the exchange of energy between kinetic and magnetic modes and (ii ) the magnetic field effect on the vorticity evolution . From these studies , it is found that magnetic field influences momentum , vorticity , and energy evolution and the degree of modification depends on the field strength . This interaction changes vortex evolution , and alters turbulence processes and rectangular jet flow characteristics . Overall , this study provides more insight into the physics of MHD flows , which suggests possible applications of MHD Flow Control .
URI: http : / /hdl .handle .net /1969 .1 /ETD -TAMU -1222
Date: 2009-05-15

Citation

Magnetohydrodynamic lattice Boltzmann simulations of turbulence and rectangular jet flow. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -1222 .

Files in this item

Files Size Format View

There are no files associated with this item.

This item appears in the following Collection(s)

Show full item record

Search DSpace

Advanced Search

Browse