Numerical investigation of flow pattern and hydrodynamic forces of submerged marine propellers using unsteady boundary element method

摘要

In this study, a numerical model of unsteady potential flow around submerged marine propellers has been developed. The boundary element approach in combination with time stepping method to model free wake dynamics has been implemented. An important feature of this method in the simulation of pressure-dominant problems is a proper balance between time and accuracy in the numerical process. Another advantage of time stepping method is that there is no need to define wake geometry before modeling. Due to inherent instability of boundary integral equations, a smoothing function to damp the effect of singularities is imposed to the solution. The main innovative idea of this work is that the effect of this mollifier function with different constants for elimination of singularity in mean induced velocity equation has been investigated. The mathematical formulation and implementation of numerical algorithm followed by a number of test cases to verify the model are presented. The results indicate good agreements between model and experiments.