New Frontiers Fellow Dr Joe Banks and PhD student Artur Lidtke represented FSI at Tokyo 2015.  The Ship Hydordynamics workshop, organised by and held at the facilities of National Maritime Research Institute (NMRI) of Japan, attracted a large number of attendees from academic and industrial backgrounds alike. Over 30 groups submitted results to allow for an assessment of the state of the art in hydrodynamic prediction methods related to ship flows. Investigated cases included the Korean Container Ship (KCS), ONR tumblehome ship (ONRT), as well as a completely new bulk carried hull, the Japanese Bulk Carrier (JBC).

The latter proved to be particularly challenging to evaluate numerically due to its high block coefficient and the resultant complex vortex structure in the wake. Most of the participants were able to predict the global forces acting on the hull and propeller with reasonable accuracy, but only the most advanced highly-resolved LES and Reynolds Stress transport RANS models were found to be capable of capturing the nature of the hook-shaped vortex in the stern region.

 The submission by the FSI group focused on the towed and self-propelled JBC cases. The former were found to agree well with similar submissions from other institutions. FSI was the only participant to evaluate the same case using more than one code using nearly-identical numerical setup and the same grid. Doing so helped to distinguish between prediction errors due to fundamental shortcomings of the RANS method used and implementation- and user-induced inaccuracies.

The Southampton maritime CFD team are the only UK based group to participate regularly in these workshops that originated from the International Towing Tank Conference in the 1980’s. They have presented their work in Gothenburg in 2000 and 2010 and previously in Tokyo in 2005.  A number of those involved in those years attended as representatives from other organisations worldwide.