https://phys.org/news/2018-07-physics-entry-smarter-ships.html

"Many studies of water entry overlook the presence of solid, stationary objects like ice or rocks in the water, and it is clear that these items can affect objects entering the water and change the physics of impact," said Maurizio Porfiri, professor of mechanical and aerospace engineering at NYU Tandon and lead author of the paper "Solid Obstacles Can Reduce Hydrodynamic Loading During Water Entry," which appears in the journal Physical Review Fluids. Porfiri's collaborators include NYU Tandon Adjunct Faculty Member Ghania Benbelkacem, in the Department of Mechanical and Aerospace Engineering, and Mohammad Jalalisendi, a recent doctoral degree graduate in Porfiri's group.

Porfiri and his collaborators in the Dynamical Systems Laboratory created an experiment using a solid wedge plunging into a tank of water containing a neutrally buoyant cylinder. Sensors in the setup measured acceleration, pressure, and depth, and the team used particle image velocimetry to visualize flow and measure the speed of water jets produced by the wedge as it hit the water. Analyses revealed that the cylinder's presence in the water dramatically changed the physics of impact on the wedge in unexpected ways.