|Title: Dynamic Extension of a Numerical Flooding Simulation in the Time-Domain|
|Written by: Hendrik Dankowski, Stefan Krüger|
|in: STAB, Glasgow 2015|
Abstract: A fast and explicit numerical flooding simulation has already been validated with the help of results from model tests and successfully applied to the investigation of several severe ship accidents like the one of the Costa Concordia. The progressive flooding method in the time-domain computes the flux between the compartments based on the Bernoulli equation combined with a quasi-static approach for the evaluation of the current floating position. The numerical method is now extended to take into account the effects of the dynamic motion of the vessel during the flooding. As it has been observed by recent model tests, the dynamic motion of the vessel might play an important role for the flooding process especially during the initial transient phase after the damage occurred. To take this into account, the hydrostatic evaluation during each time step is replaced by an integration of the equation of motions in the time-domain. The extended method will be validated with results from the model tests to demonstrate the in-fluence of the dynamic motion of the vessel on the flooding pr ocess. In addition, the new model test campaign of various flooding cases are d escribed. The enhanced method allows to give an indepth view on the dynamic propagation of the flood water after a damage to the watertight integrity of a ship occurred. Effects like the acceleration or delay of the flooding by the dynamic motion of the vessel itself are investigated. In addition, the dynamic extension is compared with the results obtained from the quasi-static approach to demonstrate the applicability of both methods. The extension of the already very powerful numerical flooding method will not only better resolve the initial phase of flooding. It will also accelerate the existing method, since the search for a new hydrostatic equilibrium is replaced by fewer volumetric calculations for the integration of the equation of motions. Applications of such a fast numerical flooding simulation in the timedomain are complex accident investigations and next generation damage stability tools to be used on-board for decision support. A reliable and fast prediction of the flooding sequence after a damage occurred assist the crew to decide whether an evacuation of the vessel is required or not.