Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

The evolution of nourished beach profile with permeable submerged breakwater in a wave flumea

Xiangke Dong a, b, Zipeng Zhang a, b, Kezhao Fang c, , Feng Yi c

State Environmental Protection Key Laboratory of Marine Ecosystem Restoration, National Marine Environmental Monitoring Center.
Dalian, Liaoning, Chinab Dalian Key Laboratory of Coastline and Coastal Wetland Restoration.
Dalian, Liaoning, Chinac
State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology.
Dalian, Liaoning, China
detailed velocity fields around and inside the obstacle has been widely
studied through numerical and physical model tests (Wu et al., 2013;Ma et al., 2014; Pourteimouri and Hejazi., 2020).
Numerical simulation has been used to simulate wavehydrodynamics and cross-shore sediment transport. Through physics
based formulas and simple diagrams of the governing processes, amodel was proposed to simulate the evolution of longshore sandbars
and the material exchange between the berm and sandbar, and calculatedune erosion, over-wash and wind-blown sand to model the evolutionof a schematized profile at a decadal scale (Larson et al, 2013; Larson
et al, 2016).
Recent studies have paid much attention to the morphologicalevolution of the shoreface nourishment and its impact on the littoral
areas. Karasu et al. (2008) developed and applied a coupled model
describing the effects of both longshore and cross-shore sedimenttransport through a series of three-dimensional laboratory experimentson beach nourishment behavior, which reproducing the salient featuresof the laboratory dataset, and previous ﬁeld data sets. Atkinson andBaldock (2020) analysed the beach profile deformation under threedifferent nourishment locations and found the shoreface nourishment
was capable of reducing shoreline recession under sea-level rise. Li etal. (2021) studied the wave dissipation and sediment transport patterns
in the evolution of shoreface nourishment towards equilibrium by thecombination of shoreface nourishment towards equilibrium. It was
found that the most intense sediment transport rate occurs over theshoreface nourishment or in front of the shoreline. An extensive
experimental and numerical research was performed to reproduce thecross-shore evolution of nourished sandy beaches, and the results showthat the impact of the submerged sill was beneficial for the beach bycausing wave breaking and energy loss, protecting the beach fromfurther erosion (Spyrou and Karambas, 2021).
Sudden placement of structure underwater sharply changes thecoastal hydrodynamics and in turn influences the sediment transportand morphological evolution. Lorenzoni et al. (2016) conducted several
physical tests to assess the fundamental features of various breakwater
configurations to be used in a beach-defence system typical of sandy,
low-coastline beaches. They analysed the main strengths andABSTRACT
The present work investigates the evolution process of beach nourishedprofile with a permeable submerged breakwater based on a physicalexperiment. A series of test cases with different configurations of thesubmerged breakwater in installation position, width and submerged
depth are conducted in a wave flume, which acquire the time series offree surface elevation and beach profile elevation. The spatial variationof wave hydrodynamics, beach behavior and morphologicalcharacteristics during the evolution of nourished beach profile areinvestigated. The effect of offshore distance, crest width and relative
submerged depth of the permeable submerged breakwater on beacherosion is discussed. The results show that the submerged breakwaterwith a bigger crest width in the middle position has the better protection
effect for preventing beach erosion, while the absolute wave height orrelative submerged depth plays a dominant role in different cases.

KEY WORDS: permeable submerged breakwater; nourished beachprofile; physical experiment; sediment transport; wave hydrodynamics.

INTRODUCTION
Sandy beaches are suffering serious erosion under the combined
action of the negative environmental impact caused by human activities
and global warming. With the continuous improvement of marine
ecological protection awareness, the beach restoration technology ofsoft protection or combination of soft and hard has attracted moreattention. As a new type of permeable structure, permeable submerged
breakwater leads to additional energy dissipation caused by porous
media, whose safety and ecology are comparable to those of traditionaldense submerged breakwater. In addition, it has been widely used due
to its lower construction cost and longer service life.
In recent years, extensive research have been carried out to reveal
wave interactions with permeable submerged breakwater. The
propagation of waves over permeable submerged breakwaters and Corresponding author.

E-mail addresses: kfang@dlut.edu.cn.

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