Marine Track: QinetiQ - James Alderton

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The information below was gathered from the 2018 Simcenter Conference - Europe that took place December 3-5, Prague, Czech Republic.


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Title: A comparison of the wind heeling moment determined through full-scale CFD against current naval stability standards

 

Naval stability standards consider the impact of a number of different external factors on an ocean-going vessel, one of which is the effect of heeling caused by wind.  With relatively large superstructures the wind heeling moment can be relatively significant, yet despite its potential impact, at present the calculation to determine the wind heeling moment is relatively simplistic.

With increasing fidelity within computational tools, in particular CFD, it questions whether the current standards are still considered fit for purpose or whether a more time consuming yet comprehensive analysis should be used.  

Work has been conducted by QinetiQ on behalf of the UK MoD to firstly benchmark the wind heeling moment derived through CFD methods using Simcenter STAR-CCM+, against existing model wind tunnel experimental results for an artificially heeled patrol boat. The benchmarking compares the level of accuracy of URANS and DES turbulence modelling, with the latter proving to provide a more accurate representation of the ships turbulent wake structure.

Following the benchmarking at model scale, CFD is used to calculate the wind heeling moment on two ships at full scale.  The two selected ships represent very different types of hullform and ship particulars.  The results from the CFD analysis are then compared to the results determined using current naval standard wind heeling criteria.  Discussed are the different CFD methodologies applied, the results from benchmarking, the comparison between the CFD results and those determined by applying current naval standard criteria, and the implications on the applicability of a CFD analysis rather than the current criteria.

The conclusions were that the current criteria could continue to be used, however the upright heeling moment used in the calculation should be determined using CFD, as the complete ship and turbulent wake is accounted for, rather than relying on a ships upright profile area.