Poster: The Hydrodynamics of High Diving

73TH ANNUAL MEETING OF THE APS DIVISION OF FLUID DYNAMICS (NOVEMBER 22, 2020 — NOVEMBER 24, 2020)When a high cliff diver enters water after a 27m-high jump, he/she has to face three main risks of injuries: first the violent impact with water surface, which forces him/her to enter the feet first: then a stretching force between his/her two legs, against which he/she has to be muscularly prepared; and finally a local increase of pressure when the air cavities collapse. In this study, the high speed imaging of the diver motion underwater, and especially the shape and dynamics of the air cavities he/she entrains crossing the air/water interface helps us to understand the hydrodynamics underlying the risks of injuries threatening the divers. Both in the lab water tank and in a real training pool, we managed to fix in time beautiful and unthinkable pictures of underwater air cavities surrounding divers' legs

The hydrodynamics of high diving

Diving consists of jumping into water from a platform, usually while performing acrobatics. During high diving competitions, the initial height reaches 27 m. From this height, the crossing of the water surface occurs at 85 km/h, and as such it is very technical to avoid injuries. Major risks occur due to the violent impact at the water entry and the formation and collapse of the air cavity around the diver. In this study, we investigate experimentally the dynamics of the jumper underwater and the hydrodynamic causes of injuries in high dives by monitoring dives from different heights with high-speed cameras and accelerometers in order to understand the physics underlying diving