Analysis of Three-Dimensional Flow around Marine Propeller by Direct Formulation of Boundary Element Method

In recent years, the fatigue fracture at the blade's root of propeller of motorcar carriers and refrigerated cargo carriers has become an important problem awaiting to be solved. Further the use of the highly skewed propeller for the reduction of ship vibration and noise leads to the strength problem of propeller. On the other hand, the demand for greater energy saving, lower propeller exciting forces and noise is growing more and more in the design of marine propeller. With such technical background, an accurate method for the calculation of the pressure distributions acting on the surface of the propeller blade has been needed. This paper presents the direct formulation of boundary element method (BEM) for the analysis of three-dimensional flow around the marine propeller which is based on the thick wing theory and expected to be a more accurate method than the lifting surface theory. The accuracy of the present method is examined by model test and full-scale experiment results. After comparison BEM calculated results, pressure distributions on the propeller blade for example, with measured ones, the accuracy and usefulness of the present method is verified.