Page 49: of Maritime Reporter Magazine (October 2015)

Marine Design Annual

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new methodology that we can measure precisely what the effect will be.”

A 2% margin of improvement in terms of frictional resistance is a big deal. “Naturally, this would not be so signi? cant for other vessel types, but the point is that the methodology is in place to simulate other factors, such as seakeeping or slamming, which may be the leading consideration for other owners,” said Niittymäki.

“Used at an early stage, CFD based on real sea states will improve design decisions on resistance in waves to optimize an entire hull form, but also save the time it takes to wait for a model basin and the cost of model testing,” said Patey. “In addition, CFD simulation is repeatable in a way that model testing is not, mean- ing that small adjustments can be easily modelled. The simulation can be run quite quickly; part of the devel- opment plan for this methodology was that it would need to be commercially applicable.”

Feeding real sea state data into Finite Element Meth- od software could be used as a design tool to address slamming and structural design issues in both the pas- senger ship and offshore context, said Patey. Model- ling using real sea state inputs could also be valuable when it comes to evaluating vibrations, and the same methodology may be adaptable to emulate the ex- treme waves experienced on rigs.

For the moment, however, Jörgensen believes atten- tion should focus on what has already been achieved. “It was truly a surprise to our hydrodynamics special- ists how close to calm seas conditions the vertical stem bow becomes preferable to the bulbous bow,” he said. “This new approach to CFD opens up signi? cant new potential for commercial ship design.” $UH6WUD\(OHFWULFDO&XUUHQWV 'HVWUR\LQJ

Sohre SHAFT GROUNDING (EARTHING) BRUSHES are used on propeller shafts, turbines, generators, electric motors, gears, pumps, etc. Failure to properly ground (earth) rotating shafts can result in expensive damage to seals, bearings, or other critical components.




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