Numerical Performance Investigations of Screw Propellers by Lifting Surface Theory

Abstract

 In conjunction with the developments in the computer technologies over the last three decades, lifting surface methods based on the circulation theory are often used for the design and analysis of screw propellers. In this study, the flow around of propeller blades is analyzed and performance characteristics of screw propellers have been examined for the different cases such as various pitch ratios, blade numbers and expanded ratios. To do this analysis, KUMS’s (Kobe University Maritime Sciences) programbased on lifting surface theory, which was generated in the Kobe University, has been used. The KUMS’s code models the flow around of the propeller by representing the blade and wake as a discrete set of vortices and sources, which are properly distributed on the mean camber and wake surfaces to represent blade loading and blade thickness respectively. Finally, a series of results have been obtained in the case of standard screw propellers and results are compared with those of experimental data whose geometric characteristics were given in the literature and PUF code written by Kerwin. Subsequently, general assessments have been done about attained results.