Modelling Extreme Free-Surface Flows: applications to breaking waves, wave-structure and wave-vessel interactions
Lead Research Organisation:
Imperial College London
Department Name: Civil & Environmental Engineering
Abstract
The proposed research concerns the description of extreme free-surface flows with applications in both deep water offshore and the shallow water coastal locations. The work will involve the development of a new numerical model appropriate to the description of large surface water waves and their interaction with both fixed structures and floating vessels. The key feature linking these flows will be the occurrence of wave breaking; involving the break-up of the water surface, the entrainment of air and the rapid development of areas of highly turbulent flow. From a practical perspective such flows are extremely important because they are associated with the highest (limiting) water surface elevations, the largest water particle velocities and the maximum applied fluid loads. As a result, they are directly relevant to the design of all manner of marine structures and vessels.In order to simulate such flows, and in so doing provide improved physical understanding, the new numerical model will combine the advantages of two very different modelling procedures: a Boundary Element Method applied before the onset of wave breaking and Smooth Particle Hydrodynamics applied to the breaking and post-breaking fluid flow. By combining these procedures the proposed method will seek to create a robust and accurate model capable of describing a wide range of free-surface flows; particular attention being paid to those aspects of wave-structure and wave-vessel interactions that are critical for design and cannot be described by existing solution procedures.The model predictions will be validated against new laboratory observations. This will involve the use of scaled physical model tests and will consider a wide range of practically important fluid flows including:(i) Breaking waves, including both large-scale over-turning and spilling waves;(ii) Highly nonlinear effects in wave-structure interaction, including high-frequency wave scattering, vertical jetting where fluid is projected upwards to very high elevations creating wave-in-deck loads, and wave slamming on both vertical columns and the deck structure;(iii) Wave-vessel interactions, particularly the occurrence of green water inundation and large impact forces.In tackling these problems, the combined experimental and numerical studies will seek to provide new physical understanding of when and why these events occur, to assess their practical implications and to identify how they can best be modelled in engineering practice.The proposed work is relevant to a wide range of problems in fluid mechanics, with particular application to the effective design and safe operation of marine structures. Direct support from three key industrial practitioners is incorporated within the proposal. The project will also be relevant to the renewable energy industry. With interest in locating offshore wind farms in areas of high wind and therefore large wave activity, such structures are very susceptible to large-scale wave breaking and the associated impact forces. The shipping industry will also benefit from this project: the new model providing information to improve the design and/or safe operation of vessels to both increase survivability and, in the case of oil tankers, limit the potential for large-scale environmental impact and damage. Finally, the work also has a truly multi-disciplinary contribution, beyond the coastal/offshore/navel architecture boundaries, in the sense that the break-up of the water surface (specifically the entrainment of air) has implications for air-sea interactions in general, and mass exchange (CO2 absorption) in particular. Such issues are of fundamental importance to oceanographers studying the transfer processes at the ocean surface and contribute a key element to climate change modelling.
People |
ORCID iD |
Christopher Swan (Principal Investigator) |
Publications
Bateman W
(2012)
Extreme ocean waves. Part I. The practical application of fully nonlinear wave modelling
in Applied Ocean Research
Christou M
(2009)
The reflection of nonlinear irregular surface water waves
in Engineering Analysis with Boundary Elements
Hague C
(2009)
A multiple flux boundary element method applied to the description of surface water waves
in Journal of Computational Physics
Katsardi V
(2010)
The evolution of large non-breaking waves in intermediate and shallow water. I. Numerical calculations of uni-directional seas
in Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Katsardi V
(2013)
An experimental study of large waves in intermediate and shallow water depths. Part I: Wave height and crest height statistics
in Coastal Engineering
Katsardi, V
(2011)
AN EXPERIMENTAL STUDY OF SHALLOW WATER WAVE STATISTICS ON MILD BED SLOPES
Latheef M
(2013)
A laboratory study of wave crest statistics and the role of directional spreading
in Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Latheef M
(2017)
A laboratory study of nonlinear changes in the directionality of extreme seas.
in Proceedings. Mathematical, physical, and engineering sciences
Latheef, M
(2011)
WAVE STATISTICS IN NONLINEAR SEA STATES
Description | Improved methods of wave modelling, including: - Crest heights, - Wave heights, - The role of directionality, - The occurrence of wave breaking, - The extreme water particle kinematics. Applying these models into load calculations has highlighted the non-conservatisms associated with present design practice. |
Exploitation Route | By their incorporation into industry standards and design guidelines. This is presently on-going. |
Sectors | Aerospace Defence and Marine Energy |
Description | Provided the basis for two new Joint Industry Funded Projects. Led to four industrially funded projects to asses the practical implications of the results in relation to the safety and reliability of specific offshore structures Led to a new methodology for the assessment of wave-in-deck loads. Presently being incorporated within the industry standard (ISO and API) design guidelines. |
First Year Of Impact | 2012 |
Sector | Aerospace, Defence and Marine,Energy |
Impact Types | Economic Policy & public services |
Description | Incorporation into the relevant International Standards Organisation (ISO) guidlines for the design of offshore structures |
Geographic Reach | Multiple continents/international |
Policy Influence Type | Participation in a guidance/advisory committee |
Impact | Improved design guidance leads to a reduced risk of failure, with both health and safety and economic implications |
Description | EPSRC (SUPERGEN) research grant: Modelling MRE devices; designing for survivability |
Amount | £1,039,617 (GBP) |
Funding ID | EP/J010197/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 05/2012 |
End | 06/2015 |
Description | Industrial CASE Award with BP. Submarine piplines: fluid-structure interactions and fluid loading |
Amount | £92,667 (GBP) |
Funding ID | Industrial CASE: voucher number 14220039 |
Organisation | BP (British Petroleum) |
Sector | Private |
Country | United Kingdom |
Start | 09/2014 |
End | 03/2018 |
Description | Industrial CASE Award with BP. Wave breaking and the effect of wave-current interactions |
Amount | £107,560 (GBP) |
Funding ID | Industrial CASE: voucher number 15220049 |
Organisation | BP (British Petroleum) |
Department | BP Exploration Company |
Sector | Private |
Country | United Kingdom |
Start | 08/2016 |
End | 03/2020 |
Description | Industrial CASE Award with Shell. Wave vessel interactions and the occurrence of wave impacts |
Amount | £107,560 (GBP) |
Funding ID | Industrial CASE voucher number 16000155 |
Organisation | Shell Global Solutions International BV |
Department | Shell Research Ltd |
Sector | Private |
Country | United Kingdom |
Start | 09/2016 |
End | 04/2020 |
Description | Industrial CASE award with BP: wave crest kinematics and extreme fluid loads |
Amount | £96,063 (GBP) |
Funding ID | BP INDUSTRIAL CASE award: Voucher Number 10000464 |
Organisation | BP (British Petroleum) |
Sector | Private |
Country | United Kingdom |
Start | 09/2011 |
End | 03/2015 |
Description | Industrial funding from BP: combined wave-current flows |
Amount | £120,000 (GBP) |
Organisation | BP (British Petroleum) |
Department | BP Marine |
Sector | Private |
Country | United Kingdom |
Start | 12/2014 |
End | 12/2016 |
Description | Industrial funding: LOWISH JIP |
Amount | £155,000 (GBP) |
Organisation | Shell Global Solutions International BV |
Department | Shell Research Ltd |
Sector | Private |
Country | United Kingdom |
Start | 09/2014 |
End | 09/2016 |
Description | Royal Society International Exchange Grant: The occurrence and intensity of surface wave breaking in realistic seas |
Amount | £12,000 (GBP) |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 03/2015 |
End | 03/2017 |
Description | Royal Society International Fellowship |
Amount | £66,000 (GBP) |
Funding ID | NF 160872 |
Organisation | The Royal Society |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 01/2017 |
End | 12/2019 |
Description | Wave-vessel interactions |
Amount | £200,000 (GBP) |
Organisation | Hyundai Heavy Industries, Ship Hydrodynamics Research Dept. |
Sector | Private |
Country | Korea, Republic of |
Start | 03/2017 |
End | 08/2020 |
Description | Joint Industry Project: Limits on waves in shallow water (LOWISH) |
Organisation | Shell Global Solutions International BV |
Department | Shell Research Ltd |
Country | United Kingdom |
Sector | Private |
PI Contribution | Laboratory observations of extreme waves in shallow water Improved understanding of wave breaking |
Collaborator Contribution | Provision of field data |
Impact | New descriptions of shallow water wave statistics New laboratory data base concerning large waves in shallow water Improved models for shallow water wave kinematics |
Start Year | 2014 |
Description | Joint Industry Project: SHORTCREST |
Organisation | Maritime Research Institute Netherlands |
Country | Netherlands |
Sector | Public |
PI Contribution | Assessment of exiting crest height models and the development of new models Understanding the role of directional spreading and incorporating it in design practice Improved wave modelling, particularly extreme kinematics high in the crests of large waves |
Collaborator Contribution | The provision of field data Laboratory data at complementary scales |
Impact | Improved models of extreme ocean waves An assessment of their importance for design applications Recommendations for updated codes of practice (ISO and API) |
Start Year | 2011 |
Description | Wave breaking: |
Organisation | Scripps Research Institute |
Country | United States |
Sector | Charity/Non Profit |
PI Contribution | Improved methods of wave generation Improved models of wave breaking and energy dissipation Insights into deep water crest height statistics |
Collaborator Contribution | Flow visualisation techniques Bubble plume analysis methods Linkage between the white cap foam area and the energy dissipation associated with breaking. |
Impact | New models for wave breaking and the associated wave energy dissipation |
Start Year | 2015 |
Description | Industrial seminar series |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Keynote address on wave-in-deck loading, organised by WS Atkins. First in a series addressing key issues in Offshore Engineering. Guest audience of 150 professionals and thereafter available on the Web. |
Year(s) Of Engagement Activity | 2014 |
Description | Offshore Structural Reliability Conference (invitation only) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | Presentation of recent advances in the description of large ocean waves and their consequences for the reliability of offshore structures |
Year(s) Of Engagement Activity | 2016 |