Regular and random wave modelling over mild uniform bathymetry using SWASH
File(s)
Published version
Author(s)
Al Khalili, Umniya
Bellos, Vasileios
Christou, Marios
Karmpadakis, Ioannis
Type
Journal Article
Abstract
The modelling of coastal waves is challenging in light of their complex behaviour driven by a range of
interacting physical effects such as nonlinear amplification, wave breaking and the influence of bathymetry.
However, their accurate modelling and understanding is fundamental in the design of coastal structures.
Many numerical models have been established to accurately capture these effects. One notable example is
SWASH, which is readily used in industry to provide insight on structural designs. The present study assesses
the applicability, validity and accuracy of SWASH to model regular and irregular waves propagating over
mild bathymetries from intermediate water depth up to the shoreline. Particular emphasis is placed on the
model’s ability to capture the effects of shoaling, wave reflection and breaking with accuracy yet reasonable
computational cost. This is addressed through an analysis into the spatial distribution of crest height and
wave height statistics. The accuracy of the numerical model is subsequently established through comparisons
to equivalent sea-states generated experimentally. SWASH is shown to perform well in modelling sea-states of
local steepness 𝐻𝑠∕𝑑 < 0.3 with 2% accuracy. However, caution should be taken in modelling steeper sea-states
dominated by breaking, where underestimation in normalised crest heights and wave heights of up to 18%
are observed compared to experimental measurements.
interacting physical effects such as nonlinear amplification, wave breaking and the influence of bathymetry.
However, their accurate modelling and understanding is fundamental in the design of coastal structures.
Many numerical models have been established to accurately capture these effects. One notable example is
SWASH, which is readily used in industry to provide insight on structural designs. The present study assesses
the applicability, validity and accuracy of SWASH to model regular and irregular waves propagating over
mild bathymetries from intermediate water depth up to the shoreline. Particular emphasis is placed on the
model’s ability to capture the effects of shoaling, wave reflection and breaking with accuracy yet reasonable
computational cost. This is addressed through an analysis into the spatial distribution of crest height and
wave height statistics. The accuracy of the numerical model is subsequently established through comparisons
to equivalent sea-states generated experimentally. SWASH is shown to perform well in modelling sea-states of
local steepness 𝐻𝑠∕𝑑 < 0.3 with 2% accuracy. However, caution should be taken in modelling steeper sea-states
dominated by breaking, where underestimation in normalised crest heights and wave heights of up to 18%
are observed compared to experimental measurements.
Date Issued
2025-06-15
Date Acceptance
2025-03-09
Citation
Coastal Engineering, 2025, 199
ISSN
0378-3839
Publisher
Elsevier BV
Journal / Book Title
Coastal Engineering
Volume
199
Copyright Statement
© 2025 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
10.1016/j.coastaleng.2025.104745
Publication Status
Published
Article Number
104745
Date Publish Online
2025-03-18