Defence in the field of mechanical engineering Pekka Kanninen M.Sc (Tech.)
Opponent Professor Rickard Bensow, Chalmers University, Sweden
Custos Professor Ville Vuorinen, Aalto University, School of Engineering, Department of Mechanical Engineering
Zoom link; https://aalto.zoom.us/j/69402400778
"Research on ship resistance An improvement of ship energy efficiency requires more advanced methods for ships’ resistance prediction. In this thesis computational fluid dynamics (CFD) for ship resistance simulation is used and factors investigated which can have affect the method’s accuracy. Due to the ship motion flow fields form around the ship which are possible to resolve by solving Navier-Stokes equations numerically. Especially, the flow phenomena in the ship wake affect the resistance. The research objective is to improve methods for two phase flow (water-air) simulation and investigate a flow phenomenon in the ship wake field. In this thesis also a supercomputer is used which enables more accurate physics in the fluid fields. In this thesis a ghost fluid method is implemented to open-source software. This method has benefits for ship-scale simulations when compared to traditional methods. Here, it was noticed that the ghost fluid method improves pressure field accuracy in the phase interfaces. By using supercomputers it is possible to simulate flow phenomena in the ship wake field more accurately. In the ship wake field occur flow phenomena which are hard to research by using model test or traditional simulation methods. The proposed simulation methods improve accuracy of the ship resistance prediction. By using the presented methods it is also possible to simulate the hull details’ resistance more accurately."