粘弾性流体の円柱周りにおける破壊と自由表面形状の関係

抄録

Fragmentation of magma is a fundamental process in volcanic eruption. Since Maxwellian viscoelasticity plays an essential role in magma fragmentation, we performed analog experiments on the fracture of viscoelastic worm-like micelle (WLM) solutions. In the experiment, the fracture caused by the movement of a cylinder inserted perpendicular to the free surface of the solution was observed by high-speed photography. Two fractures were observed, one in the fluid region and the other in the solid region. In the former, the fracture is caused by entrapped bubble in the wake of the cylinder. The fracture occurred when the aspect ratio of the bubbles reached a critical value regardless of the solution relaxation time and the diameter of the cylinder. This suggests that the free surface shape is an important parameter on the fracture.