LR has built a highly respected reputation in Computational Fluid Dynamic (CFD) simulations and is now in a leading position in ship scale CFD, having successfully delivered the first workshop in ship scale computer simulations with the application to commercial cargo vessels. However, capabilities are not limited only to merchant vessels. Over the last decade, LR has been involved in a number of projects aiming to improve design, performance and safety of passenger vessels including mega yachts through the use of CFD.
CFD can be used to assess and optimise a number of issues associated with yachts including the following:
Identifying options for reducing both hydrodynamic and aerodynamics resistance of the yacht to reduce fuel consumptions, in addition to increasing efficiency of propulsion (pictured below)
Ensuring passenger comfort on deck by assessing wind gusting, turbulence and adequate natural ventilation
Ensuring funnel emissions do not impact passenger or crew areas for any operational conditions, and the emissions are clear of ventilation intakes
Ensuring helideck wind environment is safe for helicopter operations (assessment of vertical wind gradients and turbulence to appropriate standards such as CAP 437)
Assessing fire and smoke propagation against IMO MSC.1/Circular.1533 (coupled with evacuation modelling)
An example of a recent yacht performance project LR has been involved in was assessing the safety and comfort of crew and passengers due to funnel exhaust emissions for a range of environmental conditions and engine loads. A CFD model of the yacht was constructed and exhaust dispersion was then modelled for all scenarios. The resulting concentration of the exhaust at all deck levels was then assessed against olfactory (smell) perception limits for diesel engine exhaust and regulatory safety limits for toxic gas components such as SO2.For each simulation, a stable atmospheric boundary layer profile was determined before initiating the release of exhaust gas. The simulation was run as steady state compressible flow with a multi-component gas mixture.
The CFD analysis helped to optimise the superstructure and deck arrangements in order to avoid exceeding concentration limits for SO2 and enhance passenger comfort.
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