Rim dynamics and droplet ejections upon drop impact on star-shaped poles

When a drop impacts next to the edge of a solid substrate, it spreads beyond the edge and forms a liquid sheet surrounded by a rim. As the rim decelerates, ligaments may form, then destabilize in droplets. This fragmentation scenario has been extensively investigated in the axisymmetric configuration of centered impacts on small circular targets. In this work, we investigate star-shaped targets. We show that the rim is shaped complementarily to the substrate: it goes farther and yields more droplet ejections in directions corresponding to troughs in the substrate edge profile.