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MAROFF-2-Maritim virksomhet og offsh-2

Extreme Wave Warning Criteria for Marine Structures

Alternative title: Varslingskriterier for Ekstreme Bølger for Marine Strukturer

Awarded: NOK 4.3 mill.

Project Number:

256466

Project Period:

2016 - 2020

Organisation:

The ExWaMar (EXtreme wave WArning criteria for MARine structures) project has been dedicated to development of improved warning criteria that indicate increased risk of extreme or rogue waves, relevant for shipping and offshore industries. Further, the aim of ExWaMar was to include these criteria in DNV GL Standards for marine operations as well as implement them in the forecasting system of MET Norway. Enhancing the forecast of extreme and rogue waves is of high importance for the wave forecasting services provided by MET Norway to shipping and oil companies today. The ExWaMar project was coordinated by DNV GL while MET Norway and the University of Oslo were the partners in the project. The project started 1 August 2016 and was completed 29 February 2020. During ExWaMar we developed and enhanced numerical models for simulations of ocean waves on deep, intermediate and shallow water, as well as improved description of general statistical properties of waves. These are important tools for DNV GL that can be used in number of applications in research and advisory services as well as in design and marine operations of marine structures. Finally, the past and future wave climate was investigated in the perspective of occurrence of rogue waves. Special focus was given to changes in wave spectra and wave parameters being indicators of occurrence of rogue waves. Development of warning criteria has been challenging, therefore three approaches have been investigated in parallel by the project: criteria based on the physical wave parameters which can be derived from wave forecast, criteria utilizing Machine Learning methodology, based on historical wave data, and coupling of wave forecast model and nonlinear wave numerical HOSM (Higher Order Spectral Method) code. As the latter is computational demanding today, the project concentrated on the two remaining options. The knowledge about nonlinear waves developed within the project as well as the enhanced operative HOSM code is used already in DNV GL internal and external services. Proposed ExWaMar warning criteria for extreme and rogue waves based on physical wave parameters identifying occurrence of rogue waves and using Machine Learning mehods are under validation in MET Norway operational forecast. Some of the ExWaMar results were implemented in an updated version of DNV GL RP C-205 Environmental Conditions and Environmental Loads which was issued in September 2019. The HOSM code will become a part of the DNV GL SESAM Software System. Information about the project can be found on the ExWaMar web-site: https://www.dnvgl.com/research/maritime/exwamar.html Project results were presented at: -The 5th and 6th Norway-Scotland Waves Symposium (9-10 January 2017, Oslo, Norway; 8-10 May 2019, Edinburgh, Scotland): https://www.mn.uio.no/math/english/research/groups/mechanics/events/5th-norway-scotlandwaves-symposium.html https://sites.google.com/site/6thnswaves/venue -The international conference OMAE 2017, 25-30 June 2017, Trondheim, Norway; OMAE 2018, 17-22 June 2018, Madrid, Spain; OMAE 2019, 9-14 June 2019, Glasgow, Scotland and OMAE 2020 planned to take place 28 June-3 July 2020 in Florida, USA. -The international EGU Congress EGU 2017, 23-28 April 2017; EGU 2018, 8-13 April 2018; EGU 2019, 7-12 April 2019, in Vienna, Austria. -The IOGP/JCOMM/WCRP Workshop ?Our future climate Understanding the spread of physical risk for the oil and gas industry. 25-27 September 2018, at BP Upstream Learning Centre (ULC) in Sunbury, UK. -Workshop Future Paths and Needs for Wave Modelling, 21-22 October 2019, Trondheim, Norway. https://www.sintef.no/en/events/future-paths-and-needs-in-wave-modelling/ -The 2nd International Workshop on Waves, Storm Surges and Coastal Hazards, Incorporating the 16th International Workshop on Wave Hindcasting and Forecasting, 10-15 November 2019, Melbourne, Australia. www.waveworkshop.org -Seminars for academia and the marine industry. The ExWaMar project is described in DNV GL GTR 2017 Research Review and referred in the DNV GL feature article Rethinking Rogue Waves, https://www.dnvgl.com/feature/rogue-waves.html and the February 2020 Teknisk Ukeblad article of the journalist Håvard Solerød.

The ExWaMar project has contributed to enhancement of safety at sea. The project results have increased knowledge about rogue waves and their probability of occurrence. Two alternative approaches for warning criteria for extreme and rogue waves have been proposed. The first one is employing physical wave parameters and the second approach the Machine Learning methods. MET Norway has implemented the proposed warning criteria in MET Norway operational forecast and is validating them. ExWaMar results are implemented in DNV GL RP C-205 issued in September 2019. The HOSM will become a part of the DNV GL SESAM Software System. DNV GL Maritime Advisory services are already using HOSM and the knowledge developed in ExWaMar in commercial projects. The ExWaMar project contributed to education of young people. We expect that the ExWaMar results will result in new services in DNV GL and MET Norway and bring new students to UiO as well as improve design and operations of marine structures.

ExWaMar is dedicated to development of improved warning criteria that indicate increased risk of extreme or rogue waves, relevant for shipping and offshore industries. These criteria will be included in current operational procedure for marine structures in DNV GL as well as implemented in the forecasting system of MET Norway. Enhancing the forecast of extreme and rogue waves is of high importance for the wave forecasting services provided by MET Norway to shipping and oil companies today. In the course of this project we will also develop and improve numerical models for simulations of ocean waves on deep, intermediate and shallow water, as well as improve the description of general wave statistical properties. These are important tools for DNV GL that can be used in a number of applications in research and advisory services as well as for design and marine operations. Finally, the past and future climate will be evaluated with respect to wave spectra and statistical properties of waves, contributing to the implementation of climate change in DNV GL Rules and Standards.

Funding scheme:

MAROFF-2-Maritim virksomhet og offsh-2