Spatio-temporal modelling of MetOcean environment for safe and energy efficient maritime transport
MoRE2020 Fellow Wengang Mao, outgoing mobility from Chalmers University of Technology to Osaka University, Japan
Due to the increased awareness of air emissions and economic impact from energy consumption in shipping, as well as stricter environmental regulations, the maritime community is seeking for solutions to increase energy efficiency. Furthermore, the climate targets set up by EU and Sweden require that at least 10% of the transport fuels should come from renewable sources by 2020. Since most of a ship’s service time is sailing at sea, developing energy efficiency measures in shipping must rely on a deeper fundamental understanding of the random nature of sea environment, its interaction phenomena with ship structures, as well as reliable methods to analyse the efficiency and safety of marine energy performances. This collaboration project will gather competences from sea environment observations, marine technology, and mathematical modelling at both Chalmers and Osaka University, and their surrounding maritime clusters. The objective is to develop full-time range sea environment models, which can describe and simulate the random nature and correlation structure of wind and wave conditions at both spatial and temporal regions. Several demonstration cases and virtual collaboration/dissemination platform will be created to promote the utilization of the sea environmental models for the development of innovative measures, such as ship weather routing plan, auxiliary wind propulsion technologies, etc., to promote safe and efficient maritime transport. Scientifically, the collaboration will increase our international research reputation on random sea environment modelling and application. Practically, it is also expected to build a communication bridge between maritime clusters for R&I in East Asia and VGR.
Collaborating end-users: Laurin Maritime AB, DNV GL, Lighthouse
Summary of Project Results
Most of ship safety and energy efficiency related R&D activities start with getting accurate description of Metrological and Oceanographic (MetOcean) environment that a ship will encounter during her service time for both ship design/construction and operation purpose. Extracting MetOcean information for maritime applications can be very complicated due to varying data structure/quality and inconsistent ocean parameters from different sources, etc. To overcome this problem, statistical Spatio-Temporal wind/wave models have been constructed by our research team through several EU and national projects. This model has been widely used at Chalmers to develop energy efficient measures to reduce fuel consumption and air emissions from shipping. In Japan, a similar probabilistic Storm (wave) Model has been developed during the past 20 years by researchers at Osaka University. It was later adopted by the Japanese shipping industry to investigate a ship's fatigue and fracture behavior under the random wave loads generated by their Storm Model, which is mainly for ship design and construction purposes with focus on ship safety.
During this MoRE2020 project, together with researchers from Osaka University we have systematically investigated and compared the pros and cons of these two wave models. Some advanced test facilities at Osaka University have been used to study the fatigue damage accumulation due to random wave loadings generated by both the Storm model and our Spatio-temporal model. The research results have been formulated to several scientific publications. The capabilities of our Spatio-termporal model have been presented to the Japanese shipping industry during their annual conference on Japanese Society of Naval Architectures and Ocean Engineers. Furthermore, a benchmark study case is proposed to the International Congress on Ship and Offshore Structures (ISSC) to investigate the fatigue crack propagation behavior under various statistical wave loadings applied on ships. During the project, some presentations, seminars and short summer courses have been given to Asian scholars in Japan and China to explain the background and application of our Spatio-temporal models.
However, one of the great challenges of applying our model for research activities in ship design and construction (most of today's merchant ships are constructed in East Asia) is that the statistical theory background of our Spatio-temporal model might be too complex for ship engineers to fully understand. In order to further disseminate our spatio-temporal model in East Asia and strengthen the cooperation between Chalmers and Osaka University in this field of ship design/construction and maritime transport efficiency, we have signed a formal cooperation agreement to develop a joint model to combine the advantages of both the Storm Model from Japan and the Spatio-temporal model from Chalmers. The joint model is expected to be used by research activities related to both ship safety (in Japan) and energy efficiency (in Sweden). The cooperation agreement covers two reseach units at Osaka University, i.e., Department of Naval Architecture and Ocean Engineering, and Joint and Welding Research Institute. In addition, we have sketched a project proposal to Japan JSPS and Sweden STINT joint call, to 1) Continue our current research develop, and 2) promote the students exchange between Osaka University and Chalmers within the Naval Architecture Program. In addition to Osaka University, this proposal also involves several ship design/construction companies and Japanese ship classification society. We also plan to expand our cooperation to work on develop energy efficiency measures for shipping industry.