Reliable technique to estimate near-bed kinematics for optimal design of coastal and shallow water structures

A paper detailing a new method developed by MetOcean Solutions’ Senior Physical Oceanographer, Dr Séverin Thiébaut, is being presented at the Australasian Coasts & Ports 2019 Conference, held this week in Hobart, Australia.

The research provides a reliable technique to derive near-bottom wave kinematics from surface wave spectra using non-linear theory.

“Wave-induced currents decrease from the surface to the bottom of the ocean. However they can be strong under storm conditions in shallow waters and are commonly taken into account for structure design and sediment transport assessments,” says Dr Thiébaut. 

This work contributes to improving the methodologies applied in the design of nearbed structures in coastal or shallow water environments.

“The linear approach, traditionally applied, is appropriate to calculate extreme loading conditions in deep water, however, it over simplifies the calculation in shallow waters. We apply a method that estimates extreme loading conditions from surface wave spectra as a function of water depth, wavelength, and partial significant wave height.”

Contour plots showing the relative increase when using the non-linear method ( Peak wave period   Tp  and  significant wave height   Hs ). Increasing wave heights enhance the percentage of increase when using the non-linear method.

Contour plots showing the relative increase when using the non-linear method (Peak wave period Tp and significant wave height Hs). Increasing wave heights enhance the percentage of increase when using the non-linear method.

At the conference, MetOcean Solutions’ consultancy team was also represented by Marine Project Consultancy Manager Dr Alexis Berthot and Senior Physical Oceanographers Simon Weppe and Remy Zyngfogel.

Simon presented his research on the application of SWASH (Simulation WAves till SHore) model to characterise surf break wave mechanics. Read more about his study here. Remy discussed hydrodynamic modelling in a micro-tidal salt wedge estuary - a case study of the Derwent River Estuary. Next week, further details about Remy’s research will be published at www.metocean.co.nz/news.

The Australasian Coasts and Ports 2019 brings together engineers, planners, scientists and researchers to discuss multi-disciplinary issues related to coasts and ports. The 2019 Conference theme “Future directions from 40°S and beyond” reflects the increasing awareness about the need to find suitable means for adapting to change in the “right” direction. For more information, visit https://coastsandports2019.com.au/

The full abstract can be found here. For more information, contact us at enquires@metocean.co.nz