Numerical and experimental investigations on coupled motion response of ship and sloshing inside partially flooded compartments

Partially filled internal compartments give rise to sloshing on a ship and can shift its metacentric height, causing motion and stability issues. The present study focuses on sloshing conditions inside a Ro–Ro ship as they lack bulkheads; hence, the vast open space contributes to critical instability. Liquid entrapped inside these open spaces due to internal or external damage can create a free surface effect on an intact ship; sloshing on walls can cause internal structural damage and stability variation. A study on the influence of sloshing due to different levels of trapped water inside and the effect shape of the compartment on ship motion is essential. When sloshing is large, the probability of capsizing is more at partially filled conditions. Experimental analysis was performed on a ship model with cylindrical, prismatic, and rectangular compartments. The roll and pitch responses were studied numerically for the same corresponding to head and beam sea conditions and validated. The computational study of this ship motion coupled with sloshing was performed using the numerical code FLOW3D, based on the volume of fluids (VOF) method. Compartment with internal water at 25%, 50%, and 75% of its height was studied to find coupled response RAO and peak frequency due to sloshing. It was found that the influence of sloshing of trapped water is more on the roll motion of the ship at beam sea, and the shape of the tank and fill level inside the compartment can make notable changes in ship motion.