Prediction of Slamming Behaviour of Monohull and Multihull Forms using Smoothed Particle Hydrodymamics

High-speed catamarans are increasingly being used for transportation in both defence and commercial purposes due to their advantages in fuel efficiency, speed and flexible mission applicability. Improving their seakeeping behaviour to reduce discomfort as well as keeping the structure as light as possible are two of the major issues naval architects are extensively investigating. The impact of the bow into the water when operating in large waves, better known as slamming, is a phenomenon which can cause serious damage to the structure as well as reducing passenger comfort in high-speed catamarans. Therefore an understanding of this phenomenon is crucial, as is the development of a method for accurately predicting the slam load magnitude. Model wedge water-entry experiments, CFD, mathematical and empirical formulations are conventional methods currently being employed to investigate slamming and predict drop velocity, accelerations and pressure profiles on the hull surface. More recently, the Smoothed Particle Hydrodynamics (SPH) technique has been applied to simulate wedge water-entry problems due to its advantages in capturing rapid and large deflections in fluids. In this work, SPH has been successfully used to simulate water-entry of a wedge in two-dimensions. Also, the effect of important parameters such as artificial viscosity and numberical speed of sound are investigated and comparisons with experimental results are presented. A wedge with side plates has been simulated as a simplified representation of a catamaran bow section with centrebow.