Numerical Investigation on Flood Water Sloshing Influence on Intact and Damaged Stability of Ship

Sloshing affects the intact and damage stability of the ship, which causes variation in dynamic metacentric height (GM) under critical load conditions. The transient flooding soon after the ship damage is analyzed, with floodwater accumulation in large space and causing the ship to suffer huge heel angles. The ship motion and stability changes when sloshing becomes high in partially flooded compartments. Most of the previous researches focus on the motion response of ship alone, hence the variation of stability due to sloshing is to be more critically studied. In the present study, three critical damage locations are identified and flooding through these locations are analyzed using the volume of fluids method. The method focus on finding damage ship motion response, flood water dynamics, and coupled dynamics of both. This is studied using the numerical method FLOW3D. Motion and stability behaviour will be different for different damage locations; hence portside, starboard-side, and aft-end bottom damage cases are considered. The effect of compartment shape and damage location on motion response and stability of the damaged ship is highlighted.

Time Domain Simulation of Damage Flooding Considering Air Compression Characteristics

An accurate analysis of the entire flooding process is critical to assess the damaged stability when a ship encounters distressed accidents such as collision, stranding, or grounding. Among many factors affecting the flooding process and damaged stability, the complex effect of air compression is significant and worthy of further research. In this paper, through establishing scenarios of the damage flooding for a cruise ship, the commercial software CD Adapco STARCCM+ is applied to perform time domain simulation of flooding processes under different ventilation levels. The basic mathematical models about air compression and specific simulation settings of computational fluid dynamics (CFD) are presented in detail. The simulation results show that water ingression results in an increase of air pressure and density inside the flooded compartment. The corresponding air compression can significantly delay the flooding process if the ventilation level is limited to a certain ratio. Finally, the stability of the damaged ship is affected.

A study on damaged stability of wooden fishing boats in Vietnam

In this paper, damaged stability of a Vietnamese wooden fishing boat is analyzed by a set of Theory in Register and by using the Autoship program. The purpose of this study is to optimize the distance between bulkheads to ensure the safety of the ship and also improve the economic efficiency. The authors use the Autoship program to simulate the 3D model of the ship and its positions in cases of its water flooded one or more compartments. In this study, we mostly use the Added Weight Method to define the position, the change of draft, the change of trim, the heeling and the change of stability of the ship.

Assessment of Survivability of Surface Combatants after Damage in the Sea Environment

The operating conditions of modern warships, in the natural sea environment, have a significant influence on their survivability in the event that watertight integrity is lost. Up to now, the consideration of sea and weather conditions has been implicitly accounted for in a naval ship's damaged stability assessment. This article outlines a probabilistic approach to assessing a naval ship's damage stability, in which some of the limitations of the currently used damage stability criteria are identified, including the validity of the assumption of moderate sea states at the time of damage. An investigation of the operability of a frigate design found that there is a significant increase in the risk of a ship's loss when changing the operational area from the North Atlantic to the North Pacific. A remarkable additional finding of the study showed that the assumed distribution for the damage penetration has no significant effect on the ship's survivability because of the way modern combatants are designed.

GOALDS – Goal Based Damage Stability of Passenger Ships

The new probabilistic damaged stability regulations for dry cargo and passenger ships (SOLAS 2009), which entered into force on January 1, 2009, represent a major step forward in achieving an improved safety standard through the rationalization and harmonization of damaged stability requirements. There are, however, serious concerns regarding the adopted formulation for the calculation of the survival probability of passenger ships and the associated required subdivision indices, particularly for RoPax and large cruise ships. The present paper outlines the objectives, the methodology of work and main results of the EU-funded FP7 project GOALDS (Goal Based Damage Stability, 2009-2012), which aims to address the above shortcomings by formulating a new rational, goalbased regulatory framework, properly accounting for the damage stability properties of passenger ships and the risk to people onboard.

Free Roll Decay Study of a Damaged Ship for CFD Validation

Among many factors to be considered for higher safety level requirements, the hull stability in intact and damaged conditions in seaway is of utmost importance. Since the assessment of the damaged stability is complicated due to the highly non-linear behavior, it is widely acknowledged that computational fluid dynamics (CFD) methods are the only viable approach. Although many research activities are being reported on the damaged stability recently, most of them are not designed for validation of CFD studies. In this study, well-designed model tests are performed to build a CFD validation database, which is essential in developing better CFD methods for the damaged stability assessment. The geometry of the damaged compartment and test conditions are determined based on preliminary CFD simulations. The damping coefficient of the model becomes large when the ship is damaged. The amplitude of roll motion is decreased more rapidly in damaged condition because the flooding water motion. Detailed description of the tests and corresponding conditions are described to constitute a CFD validation database.

A Numerical Study on Oil Leakage and Damaged Stability of Oil Carrier

The objective of the present paper is to carry out a study on coupled transient process of the oil leakage and the damaged stability of a crude oil carrier. For this purpose, numerical simulations based on MPS (Moving particle Semi-Implicit) method are carried out considering a two dimensional small scaled model and the oil-water multiphase flow with free surface. The results are compared with that obtained by the stability analysis software SSTAB, which provides the final list angle in case of the damage, and show good agreement.