A Numerical Study on the Influence of Caterpillars to the Resistance Performance of an Amphibious Vehicle

Abstract

A computational fluid dynamic (CFD) simulation is performed to evaluate the resistance performance of a self-propelled amphibious vessel with caterpillars to be operated as a marine debris collection vessel at hard-to-reach areas. This study focuses on the influence of the addition of caterpillars on the vessel to the resistance performance. To capture the free surface model, the volume of fluid (VOF) method was adopted, and to express the sinkage and trim acting on the ship the Dynamic Fluid-body Interaction (DFBI) model was applied. A series of numerical simulations for resistance performance were carried out in the range of Froude number (Fn) of 0.12–0.32 for the vessels with and without caterpillars. A model test was carried out independently to verify the numerical simulation of resistance, and it indicated that the present simulation is valid with relative errors of less than 2% over the entire speed range. In subsequence, the resistance performance of the ship due to the addition of the caterpillars was evaluated, and an increase of nearly 40% at the design speed of Fn = 0.27 could be observed. In addition, in the present amphibious vessel, it was found that the ratio of the pressure resistance occupied in the total resistance was dominant, reaching around 81~92% for both cases.