Pub Date : 2021-11-28DOI: 10.1080/21664250.2021.1997492
Y. Yamanaka, Y. Tajima
ABSTRACT The tide gauge data at Shirahama in Tanabe Bay on the Wakayama coast during Typhoons Jebi and Trami in 2018 showed two dominant oscillation components with periods of approximately 40–45 min and 7 min. We investigated the characteristics of the unique resonances using wavelet analysis and numerical simulations. Through the numerical simulation of storm surges by Jebi and Trami and the modeling of Trami with different tracks, we found that oscillations having a period of 40–45 min were primarily induced by the resonance in large areas, including Tanabe Bay and Kii Strait, which is north of the bay. The amplification of this large-scale resonance was sensitive to the forward speed and angle of the typhoon tracks. In addition, Green’s functions were developed to investigate local resonant characteristics in Tanabe Bay. The spatial distributions of the amplitude and phase difference of Green’s functions at different locations showed that the observed 7-min oscillations were amplified by the resonance of two adjacent small inlets at the Shirahama tide gauge station. The resonance between these two local inlets produced a long-lasting ~7-min oscillation observed at the tide gauge.
{"title":"Numerical investigation on characteristics of long wave components amplified under the 2018 Typhoons Jebi and Trami observed along the coast of Wakayama, Japan","authors":"Y. Yamanaka, Y. Tajima","doi":"10.1080/21664250.2021.1997492","DOIUrl":"https://doi.org/10.1080/21664250.2021.1997492","url":null,"abstract":"ABSTRACT The tide gauge data at Shirahama in Tanabe Bay on the Wakayama coast during Typhoons Jebi and Trami in 2018 showed two dominant oscillation components with periods of approximately 40–45 min and 7 min. We investigated the characteristics of the unique resonances using wavelet analysis and numerical simulations. Through the numerical simulation of storm surges by Jebi and Trami and the modeling of Trami with different tracks, we found that oscillations having a period of 40–45 min were primarily induced by the resonance in large areas, including Tanabe Bay and Kii Strait, which is north of the bay. The amplification of this large-scale resonance was sensitive to the forward speed and angle of the typhoon tracks. In addition, Green’s functions were developed to investigate local resonant characteristics in Tanabe Bay. The spatial distributions of the amplitude and phase difference of Green’s functions at different locations showed that the observed 7-min oscillations were amplified by the resonance of two adjacent small inlets at the Shirahama tide gauge station. The resonance between these two local inlets produced a long-lasting ~7-min oscillation observed at the tide gauge.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"100 - 115"},"PeriodicalIF":2.4,"publicationDate":"2021-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48565671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-28DOI: 10.1080/21664250.2021.2010634
Hai-jiang Liu, Zeyu Tan
ABSTRACT Existing sheet flow experimental data show the measured time-averaged suspended sediment concentration (TSSC) may increase, decrease, or even remain constant if the wave period decreases. With respect to the available sheet flow experimental data, it is confirmed that the TSSC of relatively fine sand undergoes three stages, i.e. first decreases, then increases, and finally decreases again in the case that the wave period decreases from 12 s to 2 s, whereas for the relatively coarse sand, its vertical profile remains almost unchanged. The criterion for identifying the relatively fine or coarse sand was proposed in terms of the nondimensional ratio between the settling velocity and the root-mean-square flow velocity. If this ratio is less than 0.04–0.043, it is deemed as relatively fine sand. Otherwise, it is classified as relatively coarse sand. Applying the classical gradient diffusion model, sediment diffusivity is confirmed to be insensitive to the wave period. Keeping other experimental conditions uniform, TSSCs with different wave periods are proportional to each other and only affected by the reference concentration. Subsequently, a simple quantitative expression considering the wave period effect on the TSSC under the oscillatory sheet flow regime was proposed and verified with the experimental data.
{"title":"Study of the wave period effect on the time-averaged suspended sediment concentration distribution under the oscillatory sheet flow condition","authors":"Hai-jiang Liu, Zeyu Tan","doi":"10.1080/21664250.2021.2010634","DOIUrl":"https://doi.org/10.1080/21664250.2021.2010634","url":null,"abstract":"ABSTRACT Existing sheet flow experimental data show the measured time-averaged suspended sediment concentration (TSSC) may increase, decrease, or even remain constant if the wave period decreases. With respect to the available sheet flow experimental data, it is confirmed that the TSSC of relatively fine sand undergoes three stages, i.e. first decreases, then increases, and finally decreases again in the case that the wave period decreases from 12 s to 2 s, whereas for the relatively coarse sand, its vertical profile remains almost unchanged. The criterion for identifying the relatively fine or coarse sand was proposed in terms of the nondimensional ratio between the settling velocity and the root-mean-square flow velocity. If this ratio is less than 0.04–0.043, it is deemed as relatively fine sand. Otherwise, it is classified as relatively coarse sand. Applying the classical gradient diffusion model, sediment diffusivity is confirmed to be insensitive to the wave period. Keeping other experimental conditions uniform, TSSCs with different wave periods are proportional to each other and only affected by the reference concentration. Subsequently, a simple quantitative expression considering the wave period effect on the TSSC under the oscillatory sheet flow regime was proposed and verified with the experimental data.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"260 - 271"},"PeriodicalIF":2.4,"publicationDate":"2021-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43579206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-23DOI: 10.1080/21664250.2021.2005365
D. Myrhaug, Hong Wang, L. E. Holmedal
ABSTRACT The purpose of these comments and discussion has been to demonstrate how wave statistics can be incorporated into future applications of the proposed empirical equations to estimate the maximum relative uplift pressure under positive and negative freeboards on berm revetment with Seabee slope. This is demonstrated by using a joint distribution of significant wave height and surf parameter as well as by giving examples of the results.
{"title":"Discussion/comments of «Wave-induced uplift pressure on berm revetment with Seabee slope” by Zijun Zhou, Yongping Chen, Yi Pan, Yusheng Zhen & Min Gan","authors":"D. Myrhaug, Hong Wang, L. E. Holmedal","doi":"10.1080/21664250.2021.2005365","DOIUrl":"https://doi.org/10.1080/21664250.2021.2005365","url":null,"abstract":"ABSTRACT The purpose of these comments and discussion has been to demonstrate how wave statistics can be incorporated into future applications of the proposed empirical equations to estimate the maximum relative uplift pressure under positive and negative freeboards on berm revetment with Seabee slope. This is demonstrated by using a joint distribution of significant wave height and surf parameter as well as by giving examples of the results.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"372 - 375"},"PeriodicalIF":2.4,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41744041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-23DOI: 10.1080/21664250.2021.2005364
Y. Yamanaka, T. Shimozono
ABSTRACT Tsunami source impacts in coastal areas should be investigated thoroughly; however, investigating the associated source uncertainties can incur large computational costs. This study presents a technique for rapid assessment of the impacts and their uncertainties based on a combination of the linear wave superposition for Green’s functions and a static sweep algorithm for onshore terrain. A waveform from a tsunami source is quickly estimated at a shore based on the aforementioned superposition of single-point sources simulated by a linearized Boussinesq model. The maximum water surface elevation change in the waveform, the maximum tsunami elevation, is then determined. In addition, a digital elevation model for onshore terrain that can be inundated by a tsunami is scanned using the sweep algorithm to statically compare the tsunami and ground elevations. As a result, areas with lower ground elevation than the tsunami are quickly identified as potential tsunami hazard zones. This combined analysis is applied to assess potential tsunami sources in the Japan Sea, and the source impacts are comprehensively investigated for Sakata and Akita cities in Japan. Our analysis successfully and quantitatively indicates source impacts while considering their great uncertainty. Additionally, critical areas for expanding tsunami inundation are quickly and efficiently identified.
{"title":"Rapid assessment of tsunami source impacts on low-lying coastal areas using offshore wave superposition and static sweep of onshore terrain","authors":"Y. Yamanaka, T. Shimozono","doi":"10.1080/21664250.2021.2005364","DOIUrl":"https://doi.org/10.1080/21664250.2021.2005364","url":null,"abstract":"ABSTRACT Tsunami source impacts in coastal areas should be investigated thoroughly; however, investigating the associated source uncertainties can incur large computational costs. This study presents a technique for rapid assessment of the impacts and their uncertainties based on a combination of the linear wave superposition for Green’s functions and a static sweep algorithm for onshore terrain. A waveform from a tsunami source is quickly estimated at a shore based on the aforementioned superposition of single-point sources simulated by a linearized Boussinesq model. The maximum water surface elevation change in the waveform, the maximum tsunami elevation, is then determined. In addition, a digital elevation model for onshore terrain that can be inundated by a tsunami is scanned using the sweep algorithm to statically compare the tsunami and ground elevations. As a result, areas with lower ground elevation than the tsunami are quickly identified as potential tsunami hazard zones. This combined analysis is applied to assess potential tsunami sources in the Japan Sea, and the source impacts are comprehensively investigated for Sakata and Akita cities in Japan. Our analysis successfully and quantitatively indicates source impacts while considering their great uncertainty. Additionally, critical areas for expanding tsunami inundation are quickly and efficiently identified.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"229 - 245"},"PeriodicalIF":2.4,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47784247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-17DOI: 10.1080/21664250.2021.2004037
Qiuyi Sun, X. Niu
ABSTRACT A number of observations and theoretical researches have proved that fast moving atmospheric pressure disturbances can excite large tsunami-like water waves in the coastal regions. The oscillation can become more intense inside harbors or bays due to multi-resonant mechanisms. This study mainly focuses on the impact of the disturbance heading direction on water oscillations inside a harbor. A series of cases have been numerically investigated to reveal the significance of the heading direction and the influence of other characteristic parameters. Results show that the harbor oscillation is very sensitive to the disturbance heading direction. The water response is rather intense when the disturbance moves along the coastline. In this situation, notable edge wave trains are excited nearshore and may induce significant resonance if the edge wave frequency is close to one of the eigen frequencies of the harbor. Generally, the response intensity drops with the increase in the angle between the disturbance trajectory and coastline. Meanwhile, the disturbances moving landward usually generate larger water oscillations than the seaward situations. It should be noticed that the most threatening water elevation appears when the disturbance skims over the harbor with a small angle to the coastline landward.
{"title":"Harbor oscillation induced by atmospheric pressure disturbances moving in different directions","authors":"Qiuyi Sun, X. Niu","doi":"10.1080/21664250.2021.2004037","DOIUrl":"https://doi.org/10.1080/21664250.2021.2004037","url":null,"abstract":"ABSTRACT A number of observations and theoretical researches have proved that fast moving atmospheric pressure disturbances can excite large tsunami-like water waves in the coastal regions. The oscillation can become more intense inside harbors or bays due to multi-resonant mechanisms. This study mainly focuses on the impact of the disturbance heading direction on water oscillations inside a harbor. A series of cases have been numerically investigated to reveal the significance of the heading direction and the influence of other characteristic parameters. Results show that the harbor oscillation is very sensitive to the disturbance heading direction. The water response is rather intense when the disturbance moves along the coastline. In this situation, notable edge wave trains are excited nearshore and may induce significant resonance if the edge wave frequency is close to one of the eigen frequencies of the harbor. Generally, the response intensity drops with the increase in the angle between the disturbance trajectory and coastline. Meanwhile, the disturbances moving landward usually generate larger water oscillations than the seaward situations. It should be noticed that the most threatening water elevation appears when the disturbance skims over the harbor with a small angle to the coastline landward.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"217 - 228"},"PeriodicalIF":2.4,"publicationDate":"2021-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45176768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-17DOI: 10.1080/21664250.2021.2006950
Jia-fa Shen, Hai-jiang Liu
ABSTRACT Detailed laboratory datasets of the dam break-induced surge impact pressures measured by Lobovský et al. are analyzed, upon which the dynamic amplification factors (DAF) of the single degree of freedom structures with different natural periods are calculated to quantify the dynamic responses of the measured total pressure series, the decomposed impulsive and quasi-steady pressure series based on the Hilbert-Huang transform algorithm. The maximum DAFs of the measured total and decomposed impulsive pressure series increase with the decrease of structure natural periods, while those of the decomposed quasi-steady pressure series show no relation with structure natural periods. The impulsive pressure is more influential to structures with small natural periods, whereas the quasi-steady pressure plays a predominant role regarding structures with large natural periods. Due to the resonance effect, the oscillatory pressure can significantly increase the maximum DAFs and delay its occurrence time of the measured total pressure series for structures with small natural periods. Nevertheless, the damping effect can generally decrease the DAFs of structures and therefore the resonance effect. Considering the damping coefficient varies from 0 to 0.1 in reality, increase of the maximum DAF induced by resonance is non-negligible for structures with small damping and short natural period.
{"title":"On the structure dynamic response of a coastal structure subject to the dam break induced surge impact pressure","authors":"Jia-fa Shen, Hai-jiang Liu","doi":"10.1080/21664250.2021.2006950","DOIUrl":"https://doi.org/10.1080/21664250.2021.2006950","url":null,"abstract":"ABSTRACT Detailed laboratory datasets of the dam break-induced surge impact pressures measured by Lobovský et al. are analyzed, upon which the dynamic amplification factors (DAF) of the single degree of freedom structures with different natural periods are calculated to quantify the dynamic responses of the measured total pressure series, the decomposed impulsive and quasi-steady pressure series based on the Hilbert-Huang transform algorithm. The maximum DAFs of the measured total and decomposed impulsive pressure series increase with the decrease of structure natural periods, while those of the decomposed quasi-steady pressure series show no relation with structure natural periods. The impulsive pressure is more influential to structures with small natural periods, whereas the quasi-steady pressure plays a predominant role regarding structures with large natural periods. Due to the resonance effect, the oscillatory pressure can significantly increase the maximum DAFs and delay its occurrence time of the measured total pressure series for structures with small natural periods. Nevertheless, the damping effect can generally decrease the DAFs of structures and therefore the resonance effect. Considering the damping coefficient varies from 0 to 0.1 in reality, increase of the maximum DAF induced by resonance is non-negligible for structures with small damping and short natural period.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"246 - 259"},"PeriodicalIF":2.4,"publicationDate":"2021-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47758773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-15DOI: 10.1080/21664250.2021.1997506
M. Toyoda, Nobuki Fukui, T. Miyashita, T. Shimura, N. Mori
ABSTRACT Hindcast experiments and pseudo-forecast experiments considering Typhoon Haishen (2020) were conducted using an atmospheric (WRF)-storm surge (GeoClaw) coupled model and a storm surge model with a parametric typhoon model. A series of simulations of the coupled model were used to quantify the error sources of the typhoon track and intensity in the forecast errors of storm surges. The results revealed that the typhoon track forecast had a larger error source for the storm surge forecast for the maximum surge height than the typhoon intensity. Furthermore, the parametric Holland typhoon model used in practice has an overestimation trend compared to the coupled model, and the parametric Holland typhoon model using WRF output was able to forecast the storm surge height near the typhoon (western Kyushu area) and its peak occurrence time accurately. However, the forecast accuracy tended to decrease as the distance from the typhoon to the target location increased. The pseudo-ensemble simulation of the storm surge forecast using forecast error information was conducted considering the uncertainty of the typhoon track forecast. The 20 ensemble forecast simulations revealed that the perturbed typhoon track simulation can increase the possibility of capturing the peak time of the storm surge.
{"title":"Uncertainty of storm surge forecast using integrated atmospheric and storm surge model: a case study on Typhoon Haishen 2020","authors":"M. Toyoda, Nobuki Fukui, T. Miyashita, T. Shimura, N. Mori","doi":"10.1080/21664250.2021.1997506","DOIUrl":"https://doi.org/10.1080/21664250.2021.1997506","url":null,"abstract":"ABSTRACT Hindcast experiments and pseudo-forecast experiments considering Typhoon Haishen (2020) were conducted using an atmospheric (WRF)-storm surge (GeoClaw) coupled model and a storm surge model with a parametric typhoon model. A series of simulations of the coupled model were used to quantify the error sources of the typhoon track and intensity in the forecast errors of storm surges. The results revealed that the typhoon track forecast had a larger error source for the storm surge forecast for the maximum surge height than the typhoon intensity. Furthermore, the parametric Holland typhoon model used in practice has an overestimation trend compared to the coupled model, and the parametric Holland typhoon model using WRF output was able to forecast the storm surge height near the typhoon (western Kyushu area) and its peak occurrence time accurately. However, the forecast accuracy tended to decrease as the distance from the typhoon to the target location increased. The pseudo-ensemble simulation of the storm surge forecast using forecast error information was conducted considering the uncertainty of the typhoon track forecast. The 20 ensemble forecast simulations revealed that the perturbed typhoon track simulation can increase the possibility of capturing the peak time of the storm surge.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"135 - 150"},"PeriodicalIF":2.4,"publicationDate":"2021-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43541271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-11-03DOI: 10.1080/21664250.2021.1992997
Xuejian Han, C. Kuang, Lei Zhu, L. Gong, X. Cong
ABSTRACT The beach of Shanhai Pass in the eastern Qinhuangdao, China, which was nourished in August 2017, suffered from a storm surge induced by the tropical cyclone Ampil in July 2018. In order to investigate the storm surge hydrodynamical process and the morphological response of the beach to the storm, an outer wave-current coupled model based on Delft3D and an inner morphodynamical model based on Xbeach are applied and well-validated against the measurements. The model results show that the storm-induced current vector and the wave vector at the Shanhai Pass beach rotates clockwise corresponding with the wind vector during the storm. The storm surge is positive in the north of the Bohai Sea and negative in the south when the wind speed reaches the maximum. The wind-induced surge makes the dominant contribution to the total storm surge at the study area and the air-pressure-induced surge is the second factor for far away area from the surf zone, where the wave-induced surge is negligible. The storm impact regime is determined as swash regime, and the sand of the beach foreshore is transported offshore by the storm, however, the eroded sand is transported onshore by the mild waves during the recovery period.
{"title":"Hydrodynamical and morphological patterns of a sandy coast with a beach nourishment suffering from a storm surge","authors":"Xuejian Han, C. Kuang, Lei Zhu, L. Gong, X. Cong","doi":"10.1080/21664250.2021.1992997","DOIUrl":"https://doi.org/10.1080/21664250.2021.1992997","url":null,"abstract":"ABSTRACT The beach of Shanhai Pass in the eastern Qinhuangdao, China, which was nourished in August 2017, suffered from a storm surge induced by the tropical cyclone Ampil in July 2018. In order to investigate the storm surge hydrodynamical process and the morphological response of the beach to the storm, an outer wave-current coupled model based on Delft3D and an inner morphodynamical model based on Xbeach are applied and well-validated against the measurements. The model results show that the storm-induced current vector and the wave vector at the Shanhai Pass beach rotates clockwise corresponding with the wind vector during the storm. The storm surge is positive in the north of the Bohai Sea and negative in the south when the wind speed reaches the maximum. The wind-induced surge makes the dominant contribution to the total storm surge at the study area and the air-pressure-induced surge is the second factor for far away area from the surf zone, where the wave-induced surge is negligible. The storm impact regime is determined as swash regime, and the sand of the beach foreshore is transported offshore by the storm, however, the eroded sand is transported onshore by the mild waves during the recovery period.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"83 - 99"},"PeriodicalIF":2.4,"publicationDate":"2021-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42450004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-04DOI: 10.1080/21664250.2021.1981074
Tansir Zaman Asik, M. Hussain
ABSTRACT Tropical cyclone (TC) is considered as the most dangerous and devastating hydrometeorological natural hazards in the coastal regions. On average, one severe cyclone strikes Bangladesh coast every three years. On the other hand, under significant sediment discharge from the Ganges-Brahmaputra-Meghna (GBM) River system (1.0 ~ 2.4 billion tons/year), Bengal delta dramatically changes its shorelines and bathymetry and has been gaining about 400 km2 land at the eastern part of the Meghna Estuary for the last twenty-seven (1991–2018) years. This study aims to investigate the impact of morphological changes on storm surge induced inundation characteristics on the newly reclaimed coastal lands along with different hypothetical land elevations and Sea level Rise (SLR) scenarios. Five different cyclone tracks are used to generate different cyclonic scenarios with the same strength as TC-1991. This study involves the application of the Delft-3D numerical model and ArcGIS to simulate, calculate, and visualize inundation. The results show that inundation heights strongly depend on the cyclone tracks even if the strength (wind speed and pressure drop) remains the same for all tracks. Also, with the accretion of lands, the inundation depth and extent will decrease at the mainland but increase at the accreted lands and the offshore islands, while with higher land elevation of the accreted lands, it will decrease. With SLRs, the offshore islands and accreted lands are more susceptible than the mainland. The impact of the all over land along with a 1.0 m Sea Level Rise (SLR) on the inundation depth and extent pattern will strongly depend on the elevation of the accreted lands.
{"title":"Comparative numerical simulation of storm surge inundation characteristics along the dynamic east coast of the Meghna estuary in Bangladesh","authors":"Tansir Zaman Asik, M. Hussain","doi":"10.1080/21664250.2021.1981074","DOIUrl":"https://doi.org/10.1080/21664250.2021.1981074","url":null,"abstract":"ABSTRACT Tropical cyclone (TC) is considered as the most dangerous and devastating hydrometeorological natural hazards in the coastal regions. On average, one severe cyclone strikes Bangladesh coast every three years. On the other hand, under significant sediment discharge from the Ganges-Brahmaputra-Meghna (GBM) River system (1.0 ~ 2.4 billion tons/year), Bengal delta dramatically changes its shorelines and bathymetry and has been gaining about 400 km2 land at the eastern part of the Meghna Estuary for the last twenty-seven (1991–2018) years. This study aims to investigate the impact of morphological changes on storm surge induced inundation characteristics on the newly reclaimed coastal lands along with different hypothetical land elevations and Sea level Rise (SLR) scenarios. Five different cyclone tracks are used to generate different cyclonic scenarios with the same strength as TC-1991. This study involves the application of the Delft-3D numerical model and ArcGIS to simulate, calculate, and visualize inundation. The results show that inundation heights strongly depend on the cyclone tracks even if the strength (wind speed and pressure drop) remains the same for all tracks. Also, with the accretion of lands, the inundation depth and extent will decrease at the mainland but increase at the accreted lands and the offshore islands, while with higher land elevation of the accreted lands, it will decrease. With SLRs, the offshore islands and accreted lands are more susceptible than the mainland. The impact of the all over land along with a 1.0 m Sea Level Rise (SLR) on the inundation depth and extent pattern will strongly depend on the elevation of the accreted lands.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"61 - 82"},"PeriodicalIF":2.4,"publicationDate":"2021-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48572207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-02DOI: 10.1080/21664250.2021.1991608
Kenta Sato, K. Kawasaki, Ken Watanabe, S. Koshimura
ABSTRACT Emerging as powerful open-source software in recent years, “DualSPHysics” is receiving increased attention for its ability to simulate large-scale flow fields. In the context of applying open-source software, the differences in the numerical results due to different model parameters need to be investigated in detail. In this study, some benchmark problems have been solved with DualSPHysics to validate the estimation of wave impact pressure with violent breaking waves. We have demonstrated three main results: (i) as an alternative to the artificial viscosity traditionally used in DualSPHysics, a laminar viscosity model can also well reproduce the solutions to the existing benchmark problems in a violent flow field with the modified dynamic boundary condition; (ii) the dynamics of the gas phase is essential in the calculation of wave breaking with rapid gate opening; and (iii) if the density diffusion parameter is too large, the impact pressure may be underestimated. The practical contribution by this study is to find that DualSPHysics well reproduces complex breaking waves, including multi-phase gas-liquid flows, and that the wave impact pressure is accurate by comparison with existing experimental results. This allows us to understand the complex behavior of fluid-structure interactions in coastal engineering by means of DualSPHysics.
{"title":"Validation of the applicability of the particle-based open-source software DualSPHysics to violent flow fields","authors":"Kenta Sato, K. Kawasaki, Ken Watanabe, S. Koshimura","doi":"10.1080/21664250.2021.1991608","DOIUrl":"https://doi.org/10.1080/21664250.2021.1991608","url":null,"abstract":"ABSTRACT Emerging as powerful open-source software in recent years, “DualSPHysics” is receiving increased attention for its ability to simulate large-scale flow fields. In the context of applying open-source software, the differences in the numerical results due to different model parameters need to be investigated in detail. In this study, some benchmark problems have been solved with DualSPHysics to validate the estimation of wave impact pressure with violent breaking waves. We have demonstrated three main results: (i) as an alternative to the artificial viscosity traditionally used in DualSPHysics, a laminar viscosity model can also well reproduce the solutions to the existing benchmark problems in a violent flow field with the modified dynamic boundary condition; (ii) the dynamics of the gas phase is essential in the calculation of wave breaking with rapid gate opening; and (iii) if the density diffusion parameter is too large, the impact pressure may be underestimated. The practical contribution by this study is to find that DualSPHysics well reproduces complex breaking waves, including multi-phase gas-liquid flows, and that the wave impact pressure is accurate by comparison with existing experimental results. This allows us to understand the complex behavior of fluid-structure interactions in coastal engineering by means of DualSPHysics.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"63 1","pages":"545 - 572"},"PeriodicalIF":2.4,"publicationDate":"2021-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46553051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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