WE-EXPERTH · Parallel Water Entry of Hydrophilic/Hydrophobic Projectiles: Experimental and Theoretical Aspects

Parallel Water Entry of Hydrophilic/Hydrophobic Projectiles: Experimental and Theoretical Aspects

A solid object entering a fluid like water represents a classic case of fluid-structure interaction. ‎The practical importance of water entry research extends beyond objects impacting a liquid ‎surface, and it is also ‎relevant for fixed or floating ‎structures that are exposed to the incoming ‎flow or surface waves. When an object impacts the water ‎surface, it initially pushes the upper ‎fluid layer radially outward, then accelerates the ‎surrounding fluid downward as it descends ‎into the water. This process displaces water with ‎air, creating an air-filled cavity in the object's ‎wake. During this dynamic interaction, several ‎complex and nonlinear flow phenomena arise, ‎including air-entraining cavities, splash crowns, cavity pinch-off, ‎vortex shedding, etc. These ‎phenomena influence the kinematics of the object's ‎motion. The study of water entry has ‎garnered extensive attention from academic and ‎technical researchers due to its wide range of ‎applications in various scientific and non-scientific fields. These ‎applications include industrial ‎processes such as inkjet printing, film coatings, and sprayed adhesives; naval architecture and ‎marine engineering tasks like ‎ship slamming and launching; aerospace engineering challenges ‎such as seaplane landings and ‎spacecraft water entry; sports applications like rowing oars and ‎high diving; and natural ‎phenomena observed in predaceous diving beetles, basilisk lizards, ‎and diving seabirds.‎ Most studies on water entry focus on single water entry scenarios. However, the study of dual ‎or multiple water entry—‎particularly parallel water entry, which is the focus of this research—‎is crucial in contexts such ‎as the impact of parallel oars in rowing, lifeboat water entry, ‎synchronized diving, and the ‎interaction of ocean waves with adjacent offshore structures like ‎oil rigs or wind turbine ‎towers. In these situations, differences in size, shape, or surface ‎characteristics add complexity ‎to the problem. Parallel water entry is a highly nonlinear and ‎unsteady process, with ‎significant deviations from single water entry. The interactions affect ‎air-entrainment cavities, ‎cavity pinch-off, splash curtains, and jets, as well as the trajectories of ‎the projectiles, making ‎a detailed investigation both a scientific and an engineering necessity.‎ The main objectives of this project include studying cavity dynamics and the objects' ‎‎kinetics/interaction in the context of parallel water entry of two spheres.‎ This research ‎demonstrates the significant impact of neighboring objects on the air cavity and splash sheet ‎shape, spheres' trajectories, and even descent velocities. The results provide valuable ‎information concerning the physics of the water entry process and can serve as reference cases ‎for numerical studies of parallel water entry phenomena.‎

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз