ComMotion
Over the last decade, MARIN has been work- ing together with the offshore industry and the Universities of Groningen and Delft in the development of an efficient and accurate CFD tool dedicated to the area of extreme wave loading on offshore structures, called ComFLOW. The recently started ComMotion JIP will further increase the functionality and efficiency of the ComFLOW code. The effects of structural response on impact loading will be addressed by including hydroelastic models and simulations with multiple, interactively moving bodies will be possible. Accurate current modelling will also be implemented. Additionally, algorithms for deterministic steep irregular wave generation will be further developed, resulting in a better validated and more reliable CFD tool.
ComFLOW executables will be made available to all participants of the ComMotion JIP, including code validation, benchmarking and developments that were made in previous ComFLOW JIPs. The ComMotion JIP is open to new participants and will run until end 2018.
Contact: Joop Helder,
j.helder@marin.nl
Moonpool-2
Large water motions occurring in the moon- pool when the vessel is operating or transiting in waves can be critical, as the equipment installed in the moonpool could be damaged. To minimise the risk of damage, the operations may have to be suspended, which results in a decrease of the vessel’s workability. Recently, its predecessor, the Moonpool JIP, which investigated the mechanisms leading to water motions in the moonpool, was completed successfully. However, the effect of incoming waves was not considered in this project.
Moonpool-2 aims to investigate the water oscillations occurring in the moonpool during transit and operations in waves. The objec- tives are to understand the dynamics of wave flows and loading in moonpools dur- ing transit and operations in waves, and to assess the effect of moonpool damping de- vices on workability. The JIP is expected to start in Q4, and will be conducted in close cooperation with oil companies, vessel design companies, classification societies, operators and offshore contractors.
Contact: Frédérick Jaouën,
f.jaouen@marin.nl
Wind Load
Wind loads on ships and offshore structures are traditionally studied in wind tunnel facili- ties. However, rapid development of compu- tational fluid dynamics (CFD) make it possible today to compute these forces on a powerful PC or a computer cluster. Validation of the com putational methods requires good quality benchmark data but unfortunately the available benchmark cases seem to fail the required criteria. In a number of cases an unexpected large scatter has been reported between wind tunnel tests. It is assumed that this is due to minor differences in the vertical velocity profile, turbulence intensity, blockage effects, levels of detail of the topside modelling and other difficult quantifiable parameters.
The main objective of the new Wind Load JIP is to identify and quantify these parameters. Wind tunnel tests are carried out at three dif- ferent test facilities (BMT, DNW and Peutz) and CFD calculations are performed by MARIN, Eindhoven University of Technology and a number of contri butors. The JIP will complete end-2016.
Contact: Jaap de Wilde,
j.dewilde@
marin.nl
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