Improved hull optimisation using PARNASSOS Explorer
MARIN’s in-house
RANS optimisation tool PARNASSOS
Explorer is helping the industry discover more about the optimal hull form in order to
improve performance and save energy.
T
oday, CFD-based optimisation procedures are used more and more in practical ship design pro-
jects. For many years potential flow solvers have been used routinely to optimise the front part of ships in order to minimise wave resistance for example. For the aft ship, however, where the flow is often dominated by viscous effects, viscous flow solvers have to be used.
Nowadays, it is not unusual in ship design to analyse the results of a limited number of computations, and derive recommen- dations on hull form changes from that. However, more quantifiable improvements can be obtained by automatic optimisation
procedures based on a series of CFD computations with different hull forms. This makes it possible to study any trends that are present. This is one reason MARIN decided to develop the in-house RANS optimisation tool PARNASSOS Explorer (Van der Ploeg and Raven (2010)). Multi- objective optimisation at full-scale Reynolds numbers can be performed, in which the required power to sustain a given ship speed is minimised and the quality of the inflow to the propeller is optimised by minimising the variation of the angle of attack on the propeller. The GMS-Merge tool is used, which varies hull forms by a special interpolation between some pre- defined basis hull form variants. And here
<= Better wakefield Increase variation angle of attack (%)
Christian Veldhuis & Auke van der Ploeg
c.veldhuis@
marin.nl
20 report Figure 1. Pareto front obtained with full-scale RANS/FS computations
Increase required power (%) <= decrease required power
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