Lloyd's Register's TID has been involved in a number of vibration and noise related habitability problems on feeder containerships. Propeller excitations play a major part in these vibration characteristics of container vessels and therefore it is important that radiated hull pressures are predicted accurately at the design stage. Propeller observations on a feeder container ship clearly showed the cavitation phenomena that were present, namely sheet cavitation and tip vortex cavitation. Observations with and without vortex generators stressed the important effect of the propeller inflow on propeller cavitation. Furthermore, these observations demonstrated that in-service propeller cavitation can be examined, with little effort, through TID's borescope system. Shortcomings in the traditional way of providing propeller inflows have been successfully addressed with Computational Fluid Dynamics (CFD) methods. Soon, these methods might render wake measurements at model scale obsolete and become part of routine computation procedures. Furthermore, CFD calculations can enhance our understanding of the flow and can highlight areas where caution is required when interpreting model test results.
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