A Unified Internal Flow Model with Fluid Momentum for General Application in Shipflooding and Beyond

Abstract

This paper deals with the development and validation of a unified internal flow model (UIF) for the prediction of fluid behaviour in a network of 3D floodable cells such as an internal ship compartment subdivisions. The UIF model is incorporated in a generic time-domain ship-motion simulation environment. The flow model uses cell-averaged fluid momentum to account for dynamic (inertia) effects in compartments. A compartment is typically given the size of a ship compartment on board. The fluid solver can keep track of the air pressure in and air flow through compartments under isothermal assumption. Simulation results are compared against experimental data from four different configurations: a single tank draining experiment, a two compartment down-flooding experiment, an oscillating water column experiment under pressure, and a transient flooding experiment with a cruise ship in calm water. The general validity of the UIF model is demonstrated through these four examples. The newly developed UIF model overcomes the shortcomings seen in the steady Bernoulli-based simulations. Its application leads to a more accurate prediction of the floodwater progression in the ship, and it captures the fluid dynamics seen in the oscillating water column device very well, which is not possible using the steady Bernoulli approach. The general applicability of the UIF solver for internal fluid response in maritime application is thereby demonstrated. The effect of the internal compartmentalisation of a cruise ship and the effect of viscous roll damping on the transient roll response is discussed.