Dual-Plane Stereo-PIVによる水中竜巻の流動計測(乱流渦構造(3),一般講演)

概要

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We investigated tornado-like vortex induced by a fan similar to Rushton turbine placed under the top surface of a cylindrical water tank. Experiment was performed under the condition of vortex Reynolds number being 3800 and Swirl ratio being 0.45. The three-component velocity fields in two adjacent cross-sections of the tornado-like vortex were measured by dual-plane stereo-PIV. Single vortex column was formed in the center of the tank. Instantaneous axial component of velocity at the vortex center has been fluctuated in time significantly. Such a fluctuation of the velocity was observed since the traveling wave of velocity or vorticity has been passing through. Axial pressure gradient term of Navier-Stokes equation for the axial velocity component was found to be balanced with the convection term. Thus we conclude that the fluctuation of the axial velocity component at the center of vortex was caused by local axial pressure gradient induced by the vorticity wave traveling along the vortex.
日本流体力学会の論文
2007-08-06