go to top scroll for more


Projects: Projects for Investigator
Reference Number EP/V050079/1
Title Severe Storm Wave Loads on Offshore Wind Turbine Foundations (SEA-SWALLOWS)
Status Started
Energy Categories Renewable Energy Sources(Wind Energy) 100%;
Research Types Basic and strategic applied research 100%
Science and Technology Fields PHYSICAL SCIENCES AND MATHEMATICS (Physics) 15%;
PHYSICAL SCIENCES AND MATHEMATICS (Computer Science and Informatics) 50%;
ENVIRONMENTAL SCIENCES (Earth Systems and Environmental Sciences) 5%;
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Dr J Zang
No email address given
Architecture and Civil Engineering
University of Bath
Award Type Standard
Funding Source EPSRC
Start Date 01 October 2021
End Date 30 September 2024
Duration 36 months
Total Grant Value £794,581
Industrial Sectors Construction; Water
Region South West
Programme NC : Engineering
Investigators Principal Investigator Dr J Zang , Architecture and Civil Engineering, University of Bath (99.996%)
  Other Investigator Dr T Adcock , Engineering Science, University of Oxford (0.001%)
Dr C Reale , Architecture and Civil Engineering, University of Bath (0.001%)
Dr A. H. Day , Naval Architecture & Marine Engineering, University of Strathclyde (0.001%)
Dr X Chen , Computer Science, University of Bath (0.001%)
  Industrial Collaborator Project Contact , LOC Group (London Offshore Consultants) (0.000%)
Project Contact , Shanghai Survey and Design Institute Co. - Ltd. (SIDRI), China (0.000%)
Project Contact , Bureau Veritas (0.000%)
Web Site
Abstract Offshore structures, including offshore wind turbine foundations, marine renewable energy device support structures, bridge piers, and floating vessels, are routinely exposed to harsh environmental loads. These frequently drive the design. The physics and statistics of wave-structure interaction are complex and still not fully understood for strongly non-linear loads as experienced in the most severe conditions.The particular focus of this project is fixed offshore wind turbines. These are one of the most promising sources of clean energy; and central to the UK's ambitions to become carbon neutral. The price of offshore wind has fallen significantly over the past ten years. Part of this reduction has been due to improvements in technical understanding leading to less conservative designs. Recently, there has been a trend to move to more exposed and deeper water locations with 'better' wind resources. However, such locations are susceptible to more extreme wave heights and subsequently more severe loading. These changes have increased the importance of wave loading models able to give accurate predictions of base shear and moment time-series. It is important that such models predict not only the magnitude of the load but also the correct frequency content of the loading. For instance, a large slamming load may be of sufficiently short duration that the load is not simply transmitted to the foundation. Further, structures are typically designed so as to avoid the natural frequency of the storm waves. However, if loading was to occur at higher harmonics of the fundamental wave frequencies these may coincide with the structure's natural frequencies, thus greatly increasing their importance for design. For structural fatigue assessment very long time series are required. Therefore, experimental and high-fidelity numerical models are too resource-intensive to be directly useful for practical engineering calculations. A highly efficient yet still sufficiently accurate alternative is required.The physics of wave loading is typically split into non-breaking and breaking loads. These have different magnitudes and timescales as they are dominated by different physical phenomena. For non-breaking waves, traditionally the Morison equation has been widely accepted as the starting point for calculating wave loading on offshore structures by most modern design standards. For slender cylinders in the inertia regime such as the monopiles used for offshore wind, extensions have been made to the Morison model, taking wave kinematics as inputs. Predicting wave kinematics is itself a difficult task, particularly for severe yet random sea-states where both standard regular wave stream function theory and 2nd order random wave theory are imperfect models.Breaking waves are notoriously difficult to model numerically and to measure experimentally due to the violence of the hydrodynamics and scaling issues. Various models have been proposed to simulate the time history of the loading. However, when calculating extreme responses and foundation reactions for dynamically sensitive structures, it is generally sufficient to know the total applied impulse (and where it acts) for impact loads rather than the exact time-history. Estimating the impulse is far more robust, quicker and the physics can more easily be modelled.We aim to revolutionize load calculations on offshore structures using novel fluid mechanics to develop fast reduced-order engineering models. While the focus of this work will be examining the impact of extreme wave loading on offshore wind turbine foundations, the ideas and tools generated will be more broadly applicable. We will develop a computationally fast method and an open source tool to be used by practicing engineers in industry to model long-term cyclic loading, leading to more efficient designs of offshore structures, reducing construction cost whilst preserving function and reliability.
Publications (none)
Final Report (none)
Added to Database 03/11/21