Accession Number:

AD0614838

Title:

STUDIES OF THE NOSE SHAPE OF HYDROFOIL PROFILES WHICH HAVE A WIDE NON-CAVITATING INCIDENCE RANGE,

Descriptive Note:

Corporate Author:

ENGINEERING RESEARCH ASSOCIATES TORONTO (ONTARIO)

Personal Author(s):

Report Date:

1965-03-01

Pagination or Media Count:

27.0

Abstract:

Cavitation on thin hydrofoils can be delayed to a high speed by using profiles which produce the lowest maximum fluid velocities on their surface. Such profiles usually have constant velocity distributions over much of the surface, thus avoiding peaks. However these profiles are efficient only for a narrow range of lift coefficients, and are therefore not suitable for rough water operation where changes in incidence lead to peak velocities near the leading edge. Profiles were designed for operating in a seaway by relaxing the optimum conditions at the design lift coefficient in order to obtain as wide an incidence range as possible. The leading edges of these sections appeared to be sharp, but were not defined accurately by the theory. Further studies of these profiles are given. The studies were restricted to uncambered sections with fore - and - aft symmetry. It is shown that exact linear theory leads to a negative thickness at the nose, which is physically impossible. However, a finite nose radius results when non-linear theory is used in the analysis of the leading edge region. The resultant thin profiles have a much greater incidence range than thin conventional foil sections. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE