Project PREMAN

Dipl.-Ing. Jens Höpken, Prof. Dr.-Ing. Bettar Ould el Moctar PREMAN – Scale effects and environmental conditions in connection with the prediction of the manoeuvring behaviour of sea-going ships: Sub-project MANÖ-DYN

Assuring a ship's manoeuvrability is one of the most fundamental requirements for a safe and economic vessel operation. Considering the growth in overall shipping and demand for larger ships, the necessity of predicting the vessel's manoeuvrability more precisely arises. The combined research project PREMAN is devoted to improving the prediction methods for ship manoeuvrability significantly.

The sub-project MANÖ-DYN deals with the improvement of the open source RANSE method OpenFOAM, used for the direct simulation of ship manoeuvring. The effects of the propulsion devices, the engine-propeller interaction and environmental influences, such as wind and currents, are considered in the simulations.

In order to account for the effect of the propulsion devices on the manoeuvrability, these devices need to be modelled. Modelling the propulsion devices geometrically results in a massive increase of the already high computational efforts. The propulsion devices are hence represented by a body force model that is based on a potential flow method and leads to considerably shorter simulation times.

In reality the loads on the propeller do vary substantially during manoeuvring process and the engine changes its revolutions, due to the change in torque. In order to capture this behaviour in the numerical simulations, an appropriate model is developed and coupled to the body force model.

Another focus of this project is set on the scale effects, measurements are conducted for both scales. The experimental data gained is used to validate the developed methods and their applicability. Those measurements are performed for a single screw and twin skeg ship.

The project is sponsored by the Federal Ministry for Economic Affairs and Energy.