Numerical Models in Coastal Hazards and Coastal Environment

A special issue of Journal of Marine Science and Engineering (ISSN 2077-1312). This special issue belongs to the section "Coastal Engineering".

Deadline for manuscript submissions: closed (10 July 2020) | Viewed by 51104

Special Issue Editors


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Guest Editor
Graduate School for International Development and Cooperation, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
Interests: coastal hazards; typhoons; climate change impacts on typhoons, storm surge, tsunami, and coastal flood
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Guest Editor
GeoSystem Research Corporation, 172 LS-ro, Gunpo-si 15807, Gyeonggi-do, Korea
Interests: numerical modelling; data assimilation; coupled simulation; time series analysis; environmental tracer modelling; artificial intelligence
Special Issues, Collections and Topics in MDPI journals

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Co-Guest Editor
Department of Ocean Science, Inha University, Incheon 402-751, Korea
Interests: tide; estuary; sediment; morphological change; finite element model; tsunami modeling
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

According to the UN Atlas of the Oceans, about 44% of the world’s population lives in coastal areas within 150 km of the sea. On the other hand, coastal regions are constantly exposed to natural hazards and disasters such as storm surge and waves, floods, and inundations due to tropical cyclones and storms, as well as tsunamis due to underwater earthquakes, volcanic eruptions, and landslides.

Numerical models of coastal hazards and environment are important tools for the prediction and estimation of those coastal hazards, and for the evaluation of their impacts on coastal morphodynamics, coastal lagoons and wetlands, and the coastal built-in environment.

This Special Issue seeks to compile the current state-of-the-art research related to numerical models from model developments to their applications in coastal hazards forecast and hindcast, mitigation, and in environmental impacts assessment in the above-mentioned coastal zones. Contributions are encouraged in topics including, but not limited to:

  1. Numerical models in storm surge and waves, tsunami, and coastal flooding;
  2. Numerical models in nearshore waves and currents, tide, and circulations;
  3. Numerical models of coastal pollutions;
  4. Storm surge and waves modelling due to tropical cyclones;
  5. Tsunami modelling due to underwater earthquakes, volcano eruptions, and landslides;
  6. Coastal hydrodynamic modelling in the above-mentioned coastal zones.

Prof. Dr. Han Soo Lee
Dr. Young-Jin Choi
Dr. Woo Seung-Buhm

Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Marine Science and Engineering is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • numerical models in coastal hazards and environment
  • storm surge and waves
  • tsunami
  • coastal flooding
  • nearshore waves and currents
  • tides
  • coastal hydrodynamics
  • coastal pollutions

Published Papers (14 papers)

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Editorial

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3 pages, 182 KiB  
Editorial
Numerical Models in Coastal Hazards and Coastal Environment
by Han Soo Lee, Young-Jin Choi and Seung-Buhm Woo
J. Mar. Sci. Eng. 2021, 9(5), 494; https://doi.org/10.3390/jmse9050494 - 02 May 2021
Cited by 3 | Viewed by 1659
Abstract
According to the United Nations (UN) Atlas of the Oceans, about 44% of the world’s population lives in coastal areas within 150 km of the sea [...] Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)

Research

Jump to: Editorial

16 pages, 5200 KiB  
Article
Multimodel Ensemble Projections of Wave Climate in the Western North Pacific Using CMIP6 Marine Surface Winds
by Mochamad Riam Badriana and Han Soo Lee
J. Mar. Sci. Eng. 2021, 9(8), 835; https://doi.org/10.3390/jmse9080835 - 31 Jul 2021
Cited by 6 | Viewed by 3192
Abstract
For decades, the western North Pacific (WNP) has been commonly indicated as a region with high vulnerability to oceanic and atmospheric hazards. This phenomenon can be observed through general circulation model (GCM) output from the Coupled Model Intercomparison Project (CMIP). The CMIP consists [...] Read more.
For decades, the western North Pacific (WNP) has been commonly indicated as a region with high vulnerability to oceanic and atmospheric hazards. This phenomenon can be observed through general circulation model (GCM) output from the Coupled Model Intercomparison Project (CMIP). The CMIP consists of a collection of ensemble data as well as marine surface winds for the projection of the wave climate. Wave climate projections based on the CMIP dataset are necessary for ocean studies, marine forecasts, and coastal development over the WNP region. Numerous studies with earlier phases of CMIP are abundant, but studies using CMIP6 as the recent dataset for wave projection is still limited. Thus, in this study, wave climate projections with WAVEWATCH III are conducted to investigate how wave characteristics in the WNP will have changed in 2050 and 2100 compared to those in 2000 with atmospheric forcings from CMIP6 marine surface winds. The wave model runs with a 0.5° × 0.5° spatial resolution in spherical coordinates and a 10-min time step. A total of eight GCMs from the CMIP6 dataset are used for the marine surface winds modelled over 3 h for 2050 and 2100. The simulated average wave characteristics for 2000 are validated with the ERA5 Reanalysis wave data showing good consistency. The wave characteristics in 2050 and 2100 show that significant decreases in wave height, a clockwise shift in wave direction, and the mean wave period becomes shorter relative to those in 2000. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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16 pages, 10986 KiB  
Article
Influence of Ocean Topography on Tsunami Propagation in Western Australia
by Charitha Pattiaratchi
J. Mar. Sci. Eng. 2020, 8(9), 629; https://doi.org/10.3390/jmse8090629 - 19 Aug 2020
Cited by 5 | Viewed by 3078
Abstract
Western Australia is susceptible to tsunamis from seismic sources that originate from distant sources including the Sunda Arc. Many surface and subsurface topographic ocean features are located between the Australian continent and locations where tsunamigenic earthquakes occur. These include the Venin Meinesz Seamounts [...] Read more.
Western Australia is susceptible to tsunamis from seismic sources that originate from distant sources including the Sunda Arc. Many surface and subsurface topographic ocean features are located between the Australian continent and locations where tsunamigenic earthquakes occur. These include the Venin Meinesz Seamounts (including Christmas Island) and Horizon Ridge, Exmouth, Zenith and Cuvier Plateaus. Numerical simulations of idealised tsunamigenic earthquakes along the Sunda Arc revealed that these topographic features have a large influence on the distribution of tsunami heights, propagating speeds and energy distribution. The interaction between tsunami waves and Venin Meinesz Seamounts and Horizon Ridge, located close to the earthquake locations, scatter the tsunami energy into several beams. Exmouth Plateau acts as a focusing feature to increase wave heights between North West Cape and Barrow Island whilst Cuvier Plateau deflects energy towards Shark Bay. Although Zenith Plateau has a local effect, it does not influence tsunami waves along the coast. Southwest Australia is “sheltered” from the direct effect of tsunami waves from Sunda Arc due to the combined effects of the Seamounts and Cuvier Plateau in the scattering and refraction of tsunami waves. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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16 pages, 2237 KiB  
Article
Seasonal Predictions of Shoreline Change, Informed by Climate Indices
by Dan Hilton, Mark Davidson and Tim Scott
J. Mar. Sci. Eng. 2020, 8(8), 616; https://doi.org/10.3390/jmse8080616 - 17 Aug 2020
Cited by 3 | Viewed by 2649
Abstract
With sea level rise accelerating and coastal populations increasing, the requirement of coastal managers and scientists to produce accurate predictions of shoreline change is becoming ever more urgent. Waves are the primary driver of coastal evolution, and much of the interannual variability of [...] Read more.
With sea level rise accelerating and coastal populations increasing, the requirement of coastal managers and scientists to produce accurate predictions of shoreline change is becoming ever more urgent. Waves are the primary driver of coastal evolution, and much of the interannual variability of the wave conditions in the Northeast Atlantic can be explained by broadscale patterns in atmospheric circulation. Two of the dominant climate indices that capture the wave climate in western Europe’s coastal regions are the ‘Western Europe Pressure Anomaly’ (WEPA) and ‘North Atlantic Oscillation’ (NAO). This study utilises a shoreline prediction model (ShoreFor) which is forced by synthetic waves to investigate whether forecasts can be improved when the synthetic wave generation algorithm is informed by relevant climate indices. The climate index-informed predictions were tested against a baseline case where no climate indices were considered over eight winter periods at Perranporth, UK. A simple adaption to the synthetic wave-generating process has allowed for monthly climate index values to be considered before producing the 103 random waves used to force the model. The results show that improved seasonal predictions of shoreline change are possible if climate indices are known a priori. For NAO, modest gains were made over the uninformed ShoreFor model, with a reduction in average root mean square error (RMSE) of 7% but an unchanged skill score. For WEPA, the gains were more significant, with the average RMSE 12% lower and skill score 5% higher. Highlighted is the importance of selecting an appropriate index for the site location. This work suggests that better forecasts of shoreline change could be gained from consideration of a priori knowledge of climatic indices in the generation of synthetic waves. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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15 pages, 4614 KiB  
Article
Effect of Breaking Waves on Near-Surface Mixing in an Ocean-Wave Coupling System under Calm Wind Conditions
by Ji-Seok Hong, Jae-Hong Moon and Taekyun Kim
J. Mar. Sci. Eng. 2020, 8(7), 540; https://doi.org/10.3390/jmse8070540 - 20 Jul 2020
Cited by 4 | Viewed by 2347
Abstract
Estimating wave effects on vertical mixing is a necessary step toward improving the accuracy and reliability of upper-ocean forecasts. In this study, we evaluate the wave effects on upper-ocean mixing in the northern East China Sea in summer by analyzing the results of [...] Read more.
Estimating wave effects on vertical mixing is a necessary step toward improving the accuracy and reliability of upper-ocean forecasts. In this study, we evaluate the wave effects on upper-ocean mixing in the northern East China Sea in summer by analyzing the results of comparative experiments: a stand-alone ocean model as a control run and two ocean–wave coupled models that include the effect of the breaking waves (BW) and of the wave–current interaction (WCI) with a vortex-force formalism. The comparison exhibits that under weak wind conditions, the BW effect prescribed by wave dissipation energy significantly enhances near-surface mixing because of increased downward turbulent kinetic energy (TKE), whereas the WCI has little effect on vertical mixing. Increased TKE results in a mixed-layer depth deepened by ~46% relative to the control run, which provides better agreement with the observed surface thermal structure. An additional experiment with local wind–based BW parameterization confirms the importance of nonlocally generated waves that propagated into the study area upon near-surface mixing. This suggests that under calm wind conditions, waves propagated over distances can largely affect surface vertical mixing; thus, ocean–wave coupling is capable of improving the surface thermal structure. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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15 pages, 8159 KiB  
Article
Impact of Improved Mellor–Yamada Turbulence Model on Tropical Cyclone-Induced Vertical Mixing in the Oceanic Boundary Layer
by Taekyun Kim and Jae-Hong Moon
J. Mar. Sci. Eng. 2020, 8(7), 497; https://doi.org/10.3390/jmse8070497 - 06 Jul 2020
Cited by 4 | Viewed by 2511
Abstract
It has been identified that there are several limitations in the Mellor–Yamada (MY) turbulence model applied to the atmospheric mixed layer, and Nakanishi and Niino proposed an improved MY model using a database for large-eddy simulations. The improved MY model (Mellor–Yamada–Nakanishi–Niino model; MYNN [...] Read more.
It has been identified that there are several limitations in the Mellor–Yamada (MY) turbulence model applied to the atmospheric mixed layer, and Nakanishi and Niino proposed an improved MY model using a database for large-eddy simulations. The improved MY model (Mellor–Yamada–Nakanishi–Niino model; MYNN model) is popular in atmospheric applications; however, it is rarely used in oceanic applications. In this study, the MY model and the MYNN model are compared to identify the efficiency of the MYNN model incorporated into an ocean general circulation model. To investigate the impact of the improved MY model on the vertical mixing in the oceanic boundary layer, the response of the East/Japan Sea to Typhoon Maemi in 2003 was simulated. After the typhoon event, the sea surface temperature obtained from the MYNN model showed better agreement with the satellite measurements than those obtained from the MY model. The MY model produced an extremely shallow mixed layer, and consequently, the surface temperatures were excessively warm. Furthermore, the near-inertial component of the velocity simulated using the MY model was larger than that simulated using the MYNN model at the surface layer. However, in the MYNN model, the near-inertial waves became larger than those simulated by the MY model at all depths except the surface layer. Comparatively, the MYNN model showed enhanced vertical propagation of the near-inertial activity from the mixed layer into the deep ocean, which results in a temperature decrease at the sea surface and a deepening of the mixed layer. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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20 pages, 6967 KiB  
Article
Estimating the Annual Exceedance Probability of Water Levels and Wave Heights from High Resolution Coupled Wave-Circulation Models in Long Island Sound
by Chang Liu, Yan Jia, Yaprak Onat, Alejandro Cifuentes-Lorenzen, Amin Ilia, Grant McCardell, Todd Fake and James O’Donnell
J. Mar. Sci. Eng. 2020, 8(7), 475; https://doi.org/10.3390/jmse8070475 - 27 Jun 2020
Cited by 9 | Viewed by 6000
Abstract
Accurately estimating the probability of storm surge occurrences is necessary for flood risk assessments. This research models Long Island Sound using a coupled coastal circulation and wave model (FVCOM-SWAVE) to hindcast the 44 highest storms between 1950–2018 and fitted Poisson-GPD distributions to modelled [...] Read more.
Accurately estimating the probability of storm surge occurrences is necessary for flood risk assessments. This research models Long Island Sound using a coupled coastal circulation and wave model (FVCOM-SWAVE) to hindcast the 44 highest storms between 1950–2018 and fitted Poisson-GPD distributions to modelled water levels and wave heights. Floodwater elevations and significant wave heights for 10% (1/10), 3% (1/30), 2% (1/50), and 1% (1/100) annual exceedance probabilities are provided for all Connecticut coastal towns. The results show that both water levels and their corresponding return intervals are higher along the western coast of Connecticut than the eastern coast, whereas significant wave heights increase eastward. Comparing our model results with those from the North Atlantic Coast Comprehensive Study (NACCS) shows that the mean NACCS results are higher for water levels and lower for significant wave heights for longer return periods. Likewise, the Federal Emergency Management Agency (FEMA) results in large errors compared to our results in both eastern and western coastal Connecticut regions. In addition to evaluating historical risks, we also added a sea-level height offset of 0.5 m for 2050 estimates in order to examine the effect of rising sea-levels on the analysis. We find that sea-level rise reduces the return period of a 10-year storm to two years. We advise periodically updating this work as improved sea-level rise projections become available. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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27 pages, 19528 KiB  
Article
Wave Energy in Korean Seas from 12-Year Wave Hindcasting
by Ho-Sik Eum, Weon-Mu Jeong, Yeon S. Chang, Sang-Ho Oh and Jong-Jip Park
J. Mar. Sci. Eng. 2020, 8(3), 161; https://doi.org/10.3390/jmse8030161 - 02 Mar 2020
Cited by 12 | Viewed by 4153
Abstract
In this study, a numerical simulation is performed to produce wave hindcasting data from 2007 to 2018 for the assessment of wave energy resources in the sea waters of Korea. The hindcasting data are obtained with a relatively fine spatial resolution of 1/20° [...] Read more.
In this study, a numerical simulation is performed to produce wave hindcasting data from 2007 to 2018 for the assessment of wave energy resources in the sea waters of Korea. The hindcasting data are obtained with a relatively fine spatial resolution of 1/20° covering 120–150 °E longitude and 22.4–47.6 °N latitude using the Simulating WAves Nearshore wave model (SWAN). Three different wind fields, those of the European Centre for Medium-Range Weather (ECMWF), National Centers for Environmental Prediction (NCEP), and Japan Meteorological Agency (JMA), are used for the numerical wave simulation. It is observed that the wind field dataset of JMA exhibits the best agreement with available field observation data. For this reason, the wave energy resources are evaluated based on the data hindcasted using the JMA wind field. It is found that the overall magnitudes of wave energy are larger in winter than in summer. The wave energy in August, however, is comparable to the mean wave energy during winter because of the influence of frequent high wave events caused by typhoons. The highest monthly average wave power around Yellow Sea, South Sea, East Sea, and Jeju Island are 13.3, 18.2, 13.7, and 40 kW/m, respectively. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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22 pages, 36116 KiB  
Article
Wind-Induced Currents in the Gulf of California from Extreme Events and Their Impact on Tidal Energy Devices
by Markus Gross and Vanesa Magar
J. Mar. Sci. Eng. 2020, 8(2), 80; https://doi.org/10.3390/jmse8020080 - 25 Jan 2020
Cited by 5 | Viewed by 2916
Abstract
Tidal renewable energy is a promising alternative energy resource, and marginal seas are known as excellent sites for tidal energy exploitation. In-stream and tidal energy devices are less exposed to extreme weather events than wind energy. Nevertheless, during tropical storms, the currents may [...] Read more.
Tidal renewable energy is a promising alternative energy resource, and marginal seas are known as excellent sites for tidal energy exploitation. In-stream and tidal energy devices are less exposed to extreme weather events than wind energy. Nevertheless, during tropical storms, the currents may intensify to levels that threaten the integrity of the devices. This paper presents Hurricane Odile and its impact on the currents in the Gulf of California (GC) as a worst case scenario. A methodology to analyze the impact and its potential effects on tidal energy converters installed within the region are presented. The analysis is based on predictions obtained with a 3D shallow water model forced by tides and the meteorological conditions generated by Odile. A tidal model with no wind forcing was used for validation of the tidal model predictions. After validation, the two models were used to analyze the maximum anomaly in surface currents and sea surface height caused by the passage of Odile, and to analyze at which depth the devices could be deemed safe from any impact of the hurricane. Some anomalies extended throughout the water column, even in the deep regions of the GC. This paper highlights the importance of including the meteorological forcing in evaluations of tidal range or in-stream renewable energy resources and introduces new measures of device exposure to the current anomalies. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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18 pages, 13892 KiB  
Article
Influence of Tidal Current, Wind, and Wave in Hebei Spirit Oil Spill Modeling
by Kwang-Ho Lee, Tag-Gyeom Kim and Yong-Hwan Cho
J. Mar. Sci. Eng. 2020, 8(2), 69; https://doi.org/10.3390/jmse8020069 - 22 Jan 2020
Cited by 12 | Viewed by 3580
Abstract
The purpose of this study is to investigate the effects of three external forces (tidal current, wind, and waves) on the movement of oil spilled during the Hebei Spirit oil spill accident. The diffusion of the spilled oil was simulated by using a [...] Read more.
The purpose of this study is to investigate the effects of three external forces (tidal current, wind, and waves) on the movement of oil spilled during the Hebei Spirit oil spill accident. The diffusion of the spilled oil was simulated by using a random walk (RW) model that tracks the movement caused by advection-diffusion assuming oil as particles. For oil simulation, the wind drift current generated by wind and tidal current fields were computed by using the environmental fluid dynamics code (EFDC) model. Next, the wave fields were simulated by using the simulating waves nearshore (SWAN) model, and the Stokes drift current fields were calculated by applying the equation proposed by Stokes. The computed tidal currents, wind drift currents, and Stokes drift currents were applied as input data to the RW model. Then, oil diffusion distribution for each external force component was investigated and compared with that obtained from satellite images. When the wind drift currents and Stokes drift currents caused by waves were considered, the diffusion distribution of the spilled oil showed good agreement with that obtained from the observation. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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28 pages, 3957 KiB  
Article
Modeling Storm Surge Attenuation by an Integrated Nature-Based and Engineered Flood Defense System in the Scheldt Estuary (Belgium)
by Sven Smolders, Maria João Teles, Agnès Leroy, Tatiana Maximova, Patrick Meire and Stijn Temmerman
J. Mar. Sci. Eng. 2020, 8(1), 27; https://doi.org/10.3390/jmse8010027 - 06 Jan 2020
Cited by 9 | Viewed by 5024
Abstract
There is increasing interest in the use of nature-based approaches for mitigation of storm surges along coasts, deltas, and estuaries. However, very few studies have quantified the effectiveness of storm surge height reduction by a real-existing, estuarine-scale, nature-based, and engineered flood defense system, [...] Read more.
There is increasing interest in the use of nature-based approaches for mitigation of storm surges along coasts, deltas, and estuaries. However, very few studies have quantified the effectiveness of storm surge height reduction by a real-existing, estuarine-scale, nature-based, and engineered flood defense system, under specific storm surge conditions. Here, we present data and modelling results from a specific storm surge in the Scheldt estuary (Belgium), where a hybrid flood defense system is implemented, consisting of flood control areas, of which some are restored into tidal marsh ecosystems, by use of culvert constructions that allow daily reduced tidal in- and outflow. We present a hindcast simulation of the storm surge of 6 December 2013, using a TELEMAC-3D model of the Scheldt estuary, and model scenarios showing that the hybrid flood defense system resulted in a storm surge height reduction of up to half a meter in the estuary. An important aspect of the work was the implementation of model formulations for calculating flow through culverts of restored marshes. The latter was validated comparing simulated and measured discharges through a physical scale model of a culvert, and through a real-scale culvert of an existing restored marsh during the storm surge. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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24 pages, 9210 KiB  
Article
Experimental and Numerical Investigation of Self-Burial Mechanism of Pipeline with Spoiler under Steady Flow Conditions
by Woo-Dong Lee, Hyo-Jae Jo, Han-Sol Kim, Min-Jun Kang, Kwang-Hyo Jung and Dong-Soo Hur
J. Mar. Sci. Eng. 2019, 7(12), 456; https://doi.org/10.3390/jmse7120456 - 12 Dec 2019
Cited by 11 | Viewed by 3341
Abstract
Herein, hydraulic model experiments and numerical simulations were performed to understand the self-burial mechanism of subsea pipelines with spoilers under steady flow conditions. First, scour characteristics and self-burial functions according to the spoiler length-to-pipe diameter ratio (S/D) were investigated through hydraulic [...] Read more.
Herein, hydraulic model experiments and numerical simulations were performed to understand the self-burial mechanism of subsea pipelines with spoilers under steady flow conditions. First, scour characteristics and self-burial functions according to the spoiler length-to-pipe diameter ratio (S/D) were investigated through hydraulic experiments. Further, the Navier–Stokes solver was verified. The experimental values of the velocity at the bottom of the pipeline with a spoiler and the pressure on the sand foundation where the pipeline rested were represented with the degree of conformity. Scour characteristics of a sand foundation were investigated from the numerical analysis results of the velocity and vorticity surrounding the pipelines with spoilers. The compilation of results from the hydraulic experiment and numerical analysis showed that the projected area increased when a spoiler was attached to the subsea pipes. This consequently increased the velocity of fluid leaving the top and bottom of the pipe, and high vorticity was formed within and above the sand foundation. This aggravated scouring at the pipe base and increased the top and bottom asymmetry of the dynamic pressure field, which developed a downward force on the pipeline. These two primary effects acting simultaneously under steady flow conditions explained the self-burial of pipelines with a spoiler attachment. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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17 pages, 2793 KiB  
Article
The Reproduction Ability of a Numerical Model for Simulating the Outflow Rate of Backfilling Materials from a Coastal Structure
by Kornvisith Silarom and Yoshimichi Yamamoto
J. Mar. Sci. Eng. 2019, 7(12), 447; https://doi.org/10.3390/jmse7120447 - 06 Dec 2019
Cited by 2 | Viewed by 2358
Abstract
In very shallow areas, the frequency by which coastal structures (like dikes and seawalls) are directly broken by large wave forces is low because large waves are broken in deeper areas. The main cause for such destruction is ground scour in front of [...] Read more.
In very shallow areas, the frequency by which coastal structures (like dikes and seawalls) are directly broken by large wave forces is low because large waves are broken in deeper areas. The main cause for such destruction is ground scour in front of the structures and outflow of backfilling materials by middle-scale waves; therefore, the scour and the outflow should be considered when designing a coastal structure in a very shallow area. In this paper, a numerical model consisting of CADMAS-SURF, which can calculate fluid motion in porous media, and empirical equations for simulating the outflow phenomena are introduced; thereafter, practical calculations on field cases in Thailand and Japan are demonstrated. Additionally, since the effects of wave periods and water depth to the outflow rate have never been clarified, hydraulic model experiments, empirical calculations using an existing formula, and numerical simulations are performed in order to examine these effects on the outflow rate. The simulated results using the numerical model align well with the experimental results. Moreover, both results show that the outflow rate is proportional to the wave period and inversely proportional to water depth. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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17 pages, 4187 KiB  
Article
Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century
by Carlos Antunes
J. Mar. Sci. Eng. 2019, 7(3), 61; https://doi.org/10.3390/jmse7030061 - 07 Mar 2019
Cited by 29 | Viewed by 6821
Abstract
Based on the updated relative sea level rise rates, 21st-century projections are made for the west coast of Portugal Mainland. The mean sea level from Cascais tide gauge and North Atlantic satellite altimetry data have been analyzed. Through bootstrapping linear regression and polynomial [...] Read more.
Based on the updated relative sea level rise rates, 21st-century projections are made for the west coast of Portugal Mainland. The mean sea level from Cascais tide gauge and North Atlantic satellite altimetry data have been analyzed. Through bootstrapping linear regression and polynomial adjustments, mean sea level time series were used to calculate different empirical projections for sea level rise, by estimating the initial velocity and its corresponding acceleration. The results are consistent with an accelerated sea level rise, showing evidence of a faster rise than previous century estimates. Based on different numerical methods of second order polynomial fitting, it is possible to build a set of projection models of relative sea level rise. Applying the same methods to regional sea level anomaly from satellite altimetry, additional projections are also built with good consistency. Both data sets, tide gauge and satellite altimetry data, enabled the development of an ensemble of projection models. The relative sea level rise projections are crucial for national coastal planning and management since extreme sea level scenarios can potentially cause erosion and flooding. Based on absolute vertical velocities obtained by integrating global sea level models, neo-tectonic studies, and permanent Global Positioning System (GPS) station time series, it is possible to transform relative into absolute sea level rise scenarios, and vice-versa, allowing the generation of absolute sea level rise projection curves and its comparison with already established global projections. The sea level rise observed at the Cascais tide gauge has always shown a significant correlation with global sea level rise observations, evidencing relatively low rates of vertical land velocity and residual synoptic regional dynamic effects. An ensemble of sea level projection models for the 21st century is proposed with its corresponding probability density function, both for relative and absolute sea level rise for the west coast of Portugal Mainland. A mean sea level rise of 1.14 m was obtained for the epoch of 2100, with a likely range of 95% of probability between 0.39 m and 1.89 m. Full article
(This article belongs to the Special Issue Numerical Models in Coastal Hazards and Coastal Environment)
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