Pinch-off and reconnection of axi-symmetric drops in Stokes flow

Under certain conditions, a drop in Stokes flow subject to a non-linear strain field collapses at two points on the axis, leading to a finite time pinch-off singularity. The evolution towards pinch-off is computed using a high order method with local mesh refinement, and found to satisfy a linear self-similar scaling law, as expected. A numerical method is presented to simulate the breaking of the drop at pinch-off and its reconnection into three pieces. We verify that the drop evolution after reconnection is not affected by details of the numerical method. The post reconnection recoiling process is found to satisfy a linear scaling law as well. The computed evolution of the middle drop is furthermore observed to display pinch-off at least two more times.