Numerical Investigation of Hydrodynamic Resistance of Small Passenger Vessels for Inland Waterway Tourism in Vietnam under Calm Water Conditions

Abstract

In many inland waterway tourism destinations in Vietnam, passenger transportation still relies on traditional rowing boats or small motorized vessels, whose operational efficiency and environmental performance remain limited. This study presents a CFD-based investigation of the hydrodynamic resistance characteristics of a representative small passenger vessel intended for inland tourism under calm-water conditions. The hull model was developed from surveyed vessel types currently operating in Vietnamese inland tourism areas, and its performance was evaluated over a practical service-speed range of 2.0–4.0 m/s, corresponding to the displacement, transition, and lower semi-planing regimes. The numerical simulations employed a two-phase air–water model together with a dynamic fluid–body interaction approach to capture free-surface flow and vessel motions. The results show that total resistance increases from approximately 160 N at 2.0 m/s to 578 N at 4.0 m/s, while the resistance coefficients indicate that the residual component remains dominant and the influence of pressure-related and wave-making effects becomes increasingly significant with speed. Additional analysis of wave patterns and hull-surface pressure distribution provides physical insight into the hydrodynamic mechanisms governing the resistance behavior. The obtained results contribute to establishing a baseline hydrodynamic reference for representative inland passenger vessels and provide a practical basis for preliminary propulsion-power estimation and initial electric-propulsion selection for sustainable inland tourism applications.