Seminar, Tsinghua University, Beijing, China, 22nd May 2013
From the Paddle to the Beach
Alistair G. L. Borthwick, University College Cork, Ireland
Abstract
Engineers are required to assess the run-up of beaches and overtopping of coastal structures due to extreme waves. This presentation will describe a 1-D model of wave transformation, run-up and overtopping, based on enhanced Boussinesq equations for non-breaking waves and nonlinear shallow water equations for broken waves. Wave generation is undertaken using a mapping onto a moveable grid. A wave steepness criterion is used to switch between the different sets of equations. Model verification and validation test results will be presented for solitary wave and compact wave groups. Particular consideration will be given to studies of the run-up and overtopping of solitary waves and focused wave groups at a plane beach (with and without a seawall). It will be shown that the numerical model gives satisfactory estimates of run-up and overtopping volumes in comparison with experimental data – in all cases for first-order paddle correction. Results from the numerical model will then be used to highlight the need for second-order paddle correction, and the rather major ramifications for coastal overtopping tests discussed.
Reference
Orszaghova J., Borthwick A.G.L. and Taylor P.H. (2012) From the paddle to the beach – a Boussinesq shallow water numerical wave tank based on Madsen and Sørensen’s equations. Journal of Computational Physics, 231(2): 328-344.
Brief CV
In October 2011, Alistair Borthwick took up the position of Professor of Civil and Environmental Engineering at University College Cork, Ireland. Prof. Borthwick was previously a Professor of Engineering Science at the University of Oxford, where he worked for 21 years. He remains an Emeritus Fellow at St Edmund Hall Oxford. Prof. Borthwick has more than 35 years’ experience in civil, coastal, and offshore engineering. He was a member of the design team of the Hutton Tension Leg Platform, which won the Queen’s Award for Technological Achievement in 1984. Prof. Borthwick’s research interests include shallow water-sediment flows, flood risk, coastal processes, offshore engineering, and marine renewable energy. He has co-authored more than 110 papers in peer-reviewed journals, and supervised more than 30 doctoral students to completion. In 2005, Prof. Borthwick was awarded a DSc by the University of Oxford for his sustained research in environmental fluid mechanics.
