粒子懸濁液の自由表面流れにおける粒子挙動

抄録

In this study, the suspension flows in a Hele-Shaw cell were experimentally examined. We focused on the free surface of suspension in a Hele-Shaw radial flow and discussed the effect of particle behaviors on the change in surface shape. The test fluids used were two kinds of suspension with a different particle size. The volumetric fraction of each fluid was 40 vol.%. In the observation of free surface in the Hele-Shaw flow, it was found that concave and convex parts appeared on the free surface with a time. Furthermore, at the inside region of surface undulation, the occurrence of the particle-induced viscous fingering was confirmed. Measuring velocity profiles inside the viscous fingering using the particle imaging velocimeter (PIV), we found that the velocity in the fingering region became higher than those of entire suspension. The difference between the particle velocity inside fingering and that of entire suspension suggested that the shear flow in the Hele-Shaw cell affected the particle behaviors. Furthermore, since the temporal changes in the fingering shape was different between both fluids, the particle behaviors inside the viscous fingering might relate to the particle migration in the perpendicular direction to flow direction due to the local change in the shear deformation.