Dynamically Deforming Single Jointed Diver Models Reduce Pinch off Depth
Résumé
Divers reduce visible splash and earn higher scores by performing the rip entry. The diver impacts the water perpendicular to the free surface then roll forward in a somersault as they pass through the interface. This active shape change separates divers from previously studied entry bodies. This paper investigates how this type of dynamic shape change affects the splash production with a single jointed geometrically simplified diver model that turns after impact with the free surface. The impact and splash development is captured with a high speed camera and analyzed for underwater trajectory, pinch off depth, and splash production. The results show that the dynamic shape deformation after impact reduces pinch off depth by nearly half compared to fixed diver models. We demonstrate how their dynamic deformation causes the air cavity to re-attach to the legs of the model. This changes the shape of the trailing cavity from a wedge to an hourglass, and the cavity collapse occurs at the thinnest point. A non-dimensional pinch off depth based on the arm length of the hinged model and the body length of the fixed model shows collapse of the data for all models. Our results illustrate how dynamic deformation during entry changes the essential length for cavity collapse.
Domaines
Sciences de l'ingénieur [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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