高レイノルズ数MHDチャネル乱流のDNS(流体工学,流体機械)

概要

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A direct numerical simulation (DNS) of turbulent channel flow with high Reynolds number has been carried out to show the effects of magnetic field. In this study, the Reynolds number for channel flow based on bulk velocity υ_b, kinematic viscosity ν, and channel width 2δ was set to be constant; Re_b=2δυ_b/ν=45 818. A uniform magnetic field was applied in the direction of the wall normal. The Hartman number was Ha=2δB_o√<σ/ρν>=32.5 and 65. Turbulent quantities such as the mean flow, turbulent stress, and the turbulent statistics were obtained by DNS. Although the influence of the magnetohydrodynamic dissipation terms in the turbulent kinetic energy budget was small, large-scale turbulent structures, such as vertical structures, low-speed streaks, ejection, and sweep, disappear at the central region of the channel. Consequently, the difference between production and dissipation in the turbulent kinetic energy decreases with increasing Hartmann number at the central region and large-scale structures at this region disappear.
2007-02-25