Effects of fixed and dynamic mesh methods on simulation of stepped planing craft

Abstract

In the present study, we investigate the effects of fixed and dynamic mesh methods on CFD simulation of stepped planing craft. To this accomplishment, three different body forms of without step, one step, and two step Cougar planing crafts are considered. Three-dimensional CFD analysis is conducted using finite volume method (FVM). Volume of fluid (VOF) model is used for free surface modeling. Overset mesh technique (dynamic mesh) and fixed mesh method are conducted by STAR CCM and ANSYS CFX CFD toolboxes, respectively. CFD results of total hydrodynamic resistance and dynamic trim angle are compared against our measured experimental data to assess the performance and accuracy of considered mesh methods. For more details, pressure distributions, wave patterns and streamlines around the hull models are also presented. Based on our CFD results, dynamic mesh method is more accurate and precise to simulate the stepped planing crafts compared to fixed mesh method. However, computational cost for dynamic mesh method is significantly greater than the fixed mesh method. We also found that the porpoising phenomenon is only detectable using dynamic mesh method in simulation of stepped Cougar planing craft.