Study on the motion of a freely falling horizontal cylinder into water using OpenFOAM

Abstract

The whole dropping process of a horizontal cylinder from the water surface is investigated through OpenFOAM based CFD method. A good agreement between the simulations and experimental results for a negatively buoyant (relative cylinder to water mass density, ρ'>1) falling horizontal cylinder with initial water entry velocity, Vs = 0.5 m/s, demonstrated the accuracy of the numerical model. Factors such as the initial water entry velocity, and the mass density ρ' of the cylinder relative to the water are systematically studied. The whole dropping process of horizontal cylinders with different relative mass density is simulated. Simulations are also conducted for studying a positively buoyant cylinder (ρ'<1) with various initial water entry velocity. The relative mass density and initial water entry velocity are found to have significant influence on the motion behavior, including in-plane and out-of-plane motions, hydrodynamic pressure and forces including viscous force and pressure force of the freely falling horizontal cylinder.