1465 沈降粒子がBurgers渦に与える影響について(S37-1 混相流動のダイナミックス(1),S37 混相流動のダイナミックス)  [in Japanese] 1465 Influence of a settling particle on Burgers vortex  [in Japanese]

In the present study, influence of a settling particle on Burgers vortex is observed by using 2D-PIV measurement. The vortex is the simplest model of the coherent structures. The vortex is generated in the vertical water tank. The rotational axis is directed in the gravitational direction. The vortex Reynolds number is 79. The influence of the gravitational settling near the rotational axis of the particle on the vortex is experimentally measured. We used three kinds of particles which have particle Reynolds numbers 1258, 1815 and 2854. Especially, we focus on the vorticity field and the superficial fluid divergence field induced by the particle motion on a cross-section perpendicular to the vortex axis. It is found that the maximum vorticity is increased when the particle pass through the forced vortex area, and the increase does not occur when the particle pass through the free vortex area.