Multi-Phase CFD Simulation of Lifeboat Free-Fall Launch Dynamics with Varying Pitch Angles

Abstract

The objective of this study is to simulate the free-fall launch of a lifeboat and to analyse its trajectory, pitch angle, velocity, acceleration, and pressure dynamics using Open Field Operation and Manipulation (OpenFOAM). Utilising the overset grid technique, which is well-suited for handling the expected large motions, the study employs multi-phase simulations based on the volume of fluid method. A series of 21 simulations is conducted, varying initial pitch angles and three different drop heights to thoroughly examine the lifeboat’s behaviour under various conditions. The analysis of pressure across multiple points along the same transversal and longitudinal planes reveals two significant pressure peaks: one at the bow during water entry and another at the stern, occurring after a secondary water entry triggered by turn-back spins due to restoring moments. Pressure contours indicate that the keel experiences the highest loads, highlighting it as a critical area of concern. Additionally, the kinematics of each scenario is analysed to determine which initial pitch angle would allow the lifeboat to distance itself most effectively from potential hazards without additional impulse. This aspect of the study aims to identify optimal launch conditions that enhance safety and minimise risk during emergency deployments.

Keywords

CFD simulation / Water entry / Free-fall launch / Lifeboat / Overset mesh

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