Downwash Due to a Fully Cavitated Hydrofoil Beneath a Free Surface, B. Yim, July 1963 (0129)
Two problems which have become important due to the development of supercavitating hydrofoil boats are considered. One is the form of the cavity produced by a hydrofoil under the free surface; the other is the flow field due to the cavitating hydrofoil under the free surface. These problems are so closely related that they can hardly be separated. However, the former problem has been dealt with, in the linearized version, for the case of zero cavitation number and infinite Froude number (Auslaender, 1962). For the case of finite cavity (non-zero cavitation number), and infinite Froude number, a point drag cavity model has been used to calculate the approximate size of the cavity. Also the approximate three-dimensional effect has been discussed (Yim, 1962). The latter problem, without the cavity, has been studied by Wu (1954), Maruo (1953), Nishiyam (1957), Kaplan, Breslin, and Jacobs (1960) and many others. Even without the cavity, this problem is such an immensely difficult one that it has never been fully investigated. The problem is much more difficult with the cavity. Because of this, the problems have been treated separately.