THE FORCE OF IMPACT ON A SPHERE STRIKING A WATER SURFACE
Abstract
The entry of a solid body from air into water may take place in two ways: (i) if the speed is small and if the surface of the body is smooth, the entry occurs without the formation of a cavity (smooth entry); (ii) if the speed is great or if the surface of the body is rough or has an irregular shape, the flow detaches from the body when it has penetrated a short distance below the initial surface level (rough entry). In either case there is an initial period following contact with the surface during which the body experiences the greatest deceleration and which is of such short duration that cavitation has not yet developed. It is assumed that the nose of the projectile is spherical in shape and that the initial impact with the surface is vertical. The mass of the projectile is then visualized as concentrated into a sphere of the same radius as the nose. In a previous report (PB-19651) a first approximation was obtained to the force of impact on a sphere entering vertically by disregarding the rise of the surface; in the present report, a second approximation was obtained by estimating the effects of the surface motion and the theoretical estimates are compared with experimental results.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1945
- Accession Number
- AD0605771
Entities
People
- Donald C. Spencer
- Max Shiffman
- R. Courant
Organizations
- New York University