We simulated impacts of vortex dipoles with fin rays with various distributions of bending stiffness. Figure 8A shows five panels of fin ray and dipole snapshots (distinct moments in time), for five different values of bending stiffness decay rate d. In each panel, the tracks of the dipole pair through time are shown as straight lines connecting asterisks (the dipole vortices). At the initial instant, the fin ray extends perpendicularly (horizontally) from the wall. A vortex dipole (a pair of equal and opposite point vortices of unit strength) is initially placed at one fin ray length away from the point on the fin ray 80% distal from the base. The distance between the dipole members is initially 15% of the fin ray length. These values are intended to approximate the conditions of one of the experiments (Fig. 7). The dipole is initialized at the upper right of the panel, oriented in a direction 2120 from horizontal, so that initially it travels downward and to the left, towards the fin ray. The dipole vortices diverge as they approach the fin ray. Meanwhile, the fin ray is repelled by the fluid jet between the dipole, and rotates away from it. However, the more distal, more flexible end of the fin ray is attracted to the more distal member of the dipole pair, and curls around it. A vortex sheet is continually shed from the free end of the fin ray and is shown at the final instant only as a thin gray line. The vortex sheet wraps around the distal dipole pair member (now a free vortex), while the other dipole member translates upward along the body plane. The five separate panels of Figure 8A show that when the fin ray is more flexible (left panels), it is more strongly attracted to the distal vortex. The attraction of the fin ray to the distal vortex is also seen in the experiment (Fig. 7), and may indicate a typical interaction between a flexible body and a vortex (Alben, 2012).