Marine Hydrodynamics
Marine applications share a bond with fluid mechanics, as the objects of interest – ships and floating or moored structures – operate in a fluid that can flow around them freely. Flow patterns in these cases have a significant impact on the loads that act on these objects as well as on their vibrations and large-scale motions. Such flows include the propagating waves generated by a ship advancing steadily in calm water, flows related to ships or other structures subject to waves and flows around oscillating structures such as wave energy converters or wave makers in model basins. The free surface between the water and air, which is a common characteristic of the majority of flows of interest in the field, differentiates the modelling and solution of these flow problems from other branches of fluid mechanics. Specialised algorithms and tools are required to tackle these flow problems. At the same time, the rules governing the stability of ships are evolving towards criteria based on actual performance, calling for more physics-based and realistic modelling approaches.
The goal of the research is to reach an improved understanding of flow phenomena and ship behaviour using first-principles-based modelling with an emphasis on computational methods, where computational studies are supported by experimental validation. Topics of particular interest include the modelling of waves and wave loads and the associated non-linearities – such as second-order springing and dynamic stability – of ships in both intact and damaged condition. Research related to the latter has included the study of non-linear phenomena such as parametric roll resonance, progressive flooding and the coupling of the ship and flood water motions.
First-principles-based modelling is at the core of our research and the group has produced several in-house tools for fluid flow and non-linear ship motion analysis. In addition to these in-house tools, we utilise open-source (OpenFOAM) and commercial tools. Because of the strong modelling emphasis in the group, we are also interested in the formal analysis of the reliability of simulation predictions. In this respect we are particularly interested in the behaviour of simulation error in case of free surface flows and the impact this has on the accuracy of predictions.
Personnel: Professor of Practice Pekka Ruponen, University Lecturer Tommi Mikkola