Reaction of the Wall of an Entrance Cavity Against the Afterbody of a Projectile

The cavity phase of the water entry of a projectile is described and the results are presented for the beginning of an experimental investigation of the hydrodynamic forces that affect projectile motion within a cavity. Lift-force measurements were made on two afterbody shapes that were supported so that they dug into the surface of a flowing stream of water. The similarity between these tests of models in the Free-Surface Water Tunnel and operating conditions of a full-scale projectile is discussed