Aerodynamic shapes of two-dimensional splashes

We investigate experimentally the long-term evolution of a splash induced by the water entry of 90-degree wedge of breadth $d$ and length $L$ such that $L \gg d$. We find that for large speed entry speed $V$, the splash shows both concave and convex curvature, as opposed to a single concave curvature observed for low speed. This peculiarity is found to be the result of a kink generated by the initial dynamics, the growth of which is favored by aerodynamics efforts $\rho V^2$, where $\rho$ designates the density of air, and inhibited by surface tension effects scaling as $\sigma / d$. The transition between simply-curved splash and doubly-curved splash is found to happen for Weber number $\rho V^2 d / \sigma \simeq 1$. Doubly-curved splash sheets undergo significant stretch during their life span, altering the breaking up process.