Research into changes in ship resistance in the shallow water by numerical method

Abstract

Vietnam has a long coastline and dense network of rivers and canal systems with various and complicated water depths of a waterway. According to data from the Department of Inland Waterways in 2019, Vietnam's waterways transport industry reached 250 million tons/year. In which coastal transport accounted for over 60 million tons/year, promoting the shipping industry and economic integration between regions, making the most of Vietnam's natural coastal conditions. In most general cases, the vessels working in the different water depths of the operational area will significantly affect the ship and wave field resistance. For the transport vessels with low speed, the research of the effect of resistance and wave field has an essential role in ensuring the primary maritime aim of energy saving and energy efficiency. Nowadays, computation fluid dynamics is a practical approach for predicting the ship's hydrodynamic features. However, many computation fluid dynamics types of research have investigated the ship resistance in deep water, which can not consider the effect of changing ship resistance with different water depths. In shallow water, the increasing pressure gradient field leads to an increase in the overall resistance. Therefore, in this study, the volume of fluid (VOF) multiphase model can show the free surface effect and wave elevation in shallow waters. The results clearly showed the success of the computational modeling of multiphase flows around the vessel (air and water). The wavefield in the computation fluid dynamics results is also suitable for related published research experiments. Besides, the resistance and wave elevation around the hull is significantly changing at different depths. In the preliminary design stage, it can apply this work to propose a suitable hull form of transport vessels for Vietnam's waterways.