A singular perturbation method of calculating the behavior of supercavitating hydrofoils with rounded noses

• Main Author: Furuya, Okitsugu
• Format: Others
• Published: 1972
• Online Access: https://thesis.library.caltech.edu/9663/1/Furuya_o_1972.pdf; Furuya, Okitsugu (1972) A singular perturbation method of calculating the behavior of supercavitating hydrofoils with rounded noses. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/A946-HN67. https://resolver.caltech.edu/CaltechTHESIS:04082016-141758840 <https://resolver.caltech.edu/CaltechTHESIS:04082016-141758840>

<p>A simple, direct and accurate method to predict the pressure distribution on supercavitating hydrofoils with rounded noses is presented. The thickness of body and cavity is assumed to be small. The method adopted in the present work is that of singular perturbation theory. Far from the leading edge linearized free streamline theory is applied. Near the leading edge, however, where singularities of the linearized theory occur, a non-linear local solution is employed. The two unknown parameters which characterize this local solution are determined by a matching procedure. A uniformly valid solution is then constructed with the aid of the singular perturbation approach.</p> <p>The present work is divided into two parts. In Part I isolated supercavitating hydrofoils of arbitrary profile shape with parabolic noses are investigated by the present method and its results are compared with the new computational results made with Wu and Wang's exact "functional iterative" method. The agreement is very good. In Part II this method is applied to a linear cascade of such hydrofoils with elliptic noses. A number of cases are worked out over a range of cascade parameters from which a good idea of the behavior of this type of important flow configuration is obtained.</p> <p>Some of the computational aspects of Wu and Wang's functional iterative method heretofore not successfully applied to this type of problem are described in an appendix.</p>