Pub Date : 2022-04-03DOI: 10.1080/21664250.2022.2072611
Masashi Watanabe, T. Arikawa, Naoto Kihara, Chiaki Tsurudome, Koichi Hosaka, Tatsuto Kimura, Takayuki Hashimoto, Fumitaka Ishihara, Takemi Shikata, D. Morikawa, Taiga Makino, M. Asai, Y. Chida, Yoichi Ohnishi, S. Marras, Abhishek Mukherjee, J. Cajas, G. Houzeaux, B. D. Paolo, J. Lara, G. Barajas, I. Losada, M. Hasebe, Y. Shigihara, T. Asai, T. Ikeya, Shusaku Inoue, H. Matsutomi, Y. Nakano, Y. Okuda, Shunya Okuno, Takayuki Ooie, G. Shoji, T. Tateno
ABSTRACT Numerous tsunami numerical models have been proposed, but their prediction accuracies have not been directly compared. For quantifying the modeling uncertainties, the authors statistically analyzed the prediction results submitted by participants in the tsunami blind contest held at the 17th World Conference on Earthquake Engineering. The reproducibility of offshore water level generated due to the tsunami with soliton fission significantly decreased when the nonlinear shallow water equation models (NSWE) was used compared to three-dimensional (3D) models. The inundation depth was reproduced well in 3D models. However, the reproducibility of wave forces acting on the structure and velocities over land was lower in 3D models than that in NSWE models. For cases where the impulsive tsunami wave pressure generated could not be calculated based on the hydrostatic assumption, the prediction accuracy of the NSWE models was higher than that of the 3D models. The prediction accuracies of both models were not improved at small grid-cell sizes. The NSWE model cannot simulate the short-wave component and vertical pressure distribution. Therefore, further developments in 3D models and smoothed particle hydrodynamics methods (SPH) are needed. The presented results contribute to the future development of tsunami numerical simulation tools.
{"title":"Validation of tsunami numerical simulation models for an idealized coastal industrial site","authors":"Masashi Watanabe, T. Arikawa, Naoto Kihara, Chiaki Tsurudome, Koichi Hosaka, Tatsuto Kimura, Takayuki Hashimoto, Fumitaka Ishihara, Takemi Shikata, D. Morikawa, Taiga Makino, M. Asai, Y. Chida, Yoichi Ohnishi, S. Marras, Abhishek Mukherjee, J. Cajas, G. Houzeaux, B. D. Paolo, J. Lara, G. Barajas, I. Losada, M. Hasebe, Y. Shigihara, T. Asai, T. Ikeya, Shusaku Inoue, H. Matsutomi, Y. Nakano, Y. Okuda, Shunya Okuno, Takayuki Ooie, G. Shoji, T. Tateno","doi":"10.1080/21664250.2022.2072611","DOIUrl":"https://doi.org/10.1080/21664250.2022.2072611","url":null,"abstract":"ABSTRACT Numerous tsunami numerical models have been proposed, but their prediction accuracies have not been directly compared. For quantifying the modeling uncertainties, the authors statistically analyzed the prediction results submitted by participants in the tsunami blind contest held at the 17th World Conference on Earthquake Engineering. The reproducibility of offshore water level generated due to the tsunami with soliton fission significantly decreased when the nonlinear shallow water equation models (NSWE) was used compared to three-dimensional (3D) models. The inundation depth was reproduced well in 3D models. However, the reproducibility of wave forces acting on the structure and velocities over land was lower in 3D models than that in NSWE models. For cases where the impulsive tsunami wave pressure generated could not be calculated based on the hydrostatic assumption, the prediction accuracy of the NSWE models was higher than that of the 3D models. The prediction accuracies of both models were not improved at small grid-cell sizes. The NSWE model cannot simulate the short-wave component and vertical pressure distribution. Therefore, further developments in 3D models and smoothed particle hydrodynamics methods (SPH) are needed. The presented results contribute to the future development of tsunami numerical simulation tools.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"302 - 343"},"PeriodicalIF":2.4,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42702968","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 : 2022-04-03DOI: 10.1080/21664250.2022.2044580
N. Talebbeydokhti, M. Feizi, S. M. Amiri, B. Chopard
ABSTRACT Various numerical methods for modeling wave propagation are presented in the literature. These models are specified by the inclusion of nonlinearity and dispersion. The nonlinear Shallow Water Equations (SWEs) and Boussinesq equations are two main sets for wave-based problems. Lattice Boltzmann Method (LBM) is a productive method for solving various CFD problems like issues in the field of free-surface flow problems, that is derived for SWEs in the literature and solved by various numerical methods. In the present study, the 1-D extended Boussinesq system of equations is used as the base equation. Then, this system of equation is converted to Lattice Boltzmann form for the first time. The meshless Element-Free Galerkin (EFG) form of the converted equation is derived and used as the numerical method for wave propagation problems to cover the discontinuous nature of the wave problems. The new orthogonal moving least approximations is defined for the EFG method to avoid singularity in the simulations. Various examples are simulated by the presented numerical model and compared with experimental and other numerical methods. As illustrated in detail in the text, there is high accuracy between the presented results with the experimental and numerical data.
{"title":"Simulation of 1-D wave propagation by Meshless Lattice Boltzmann method based on Extended Boussinesq equations","authors":"N. Talebbeydokhti, M. Feizi, S. M. Amiri, B. Chopard","doi":"10.1080/21664250.2022.2044580","DOIUrl":"https://doi.org/10.1080/21664250.2022.2044580","url":null,"abstract":"ABSTRACT Various numerical methods for modeling wave propagation are presented in the literature. These models are specified by the inclusion of nonlinearity and dispersion. The nonlinear Shallow Water Equations (SWEs) and Boussinesq equations are two main sets for wave-based problems. Lattice Boltzmann Method (LBM) is a productive method for solving various CFD problems like issues in the field of free-surface flow problems, that is derived for SWEs in the literature and solved by various numerical methods. In the present study, the 1-D extended Boussinesq system of equations is used as the base equation. Then, this system of equation is converted to Lattice Boltzmann form for the first time. The meshless Element-Free Galerkin (EFG) form of the converted equation is derived and used as the numerical method for wave propagation problems to cover the discontinuous nature of the wave problems. The new orthogonal moving least approximations is defined for the EFG method to avoid singularity in the simulations. Various examples are simulated by the presented numerical model and compared with experimental and other numerical methods. As illustrated in detail in the text, there is high accuracy between the presented results with the experimental and numerical data.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"285 - 301"},"PeriodicalIF":2.4,"publicationDate":"2022-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46071225","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 : 2022-02-06DOI: 10.1080/21664250.2022.2035514
M. Toyoda, N. Mori, J. Yoshino
ABSTRACT This study proposes empirical relations for the ratio of the radius of maximum pressure gradient to the radius of maximum wind speed for the empirical typhoon model (ETM) based on the results of analysis of multiple typhoons obtained from the meteorological model. One proposed relation was parameterized based on the attenuation rate from the peak time to landfall time. The other was parameterized based on the distance from where the typhoon reached its peak intensity to the coastline. These relationships are useful for practical applications. In addition, the typhoon pressure shape parameter B was calculated from the constructed equations and the relational equation proposed by Holland. The improvement in accuracy, as compared with conventional ETM (B = 1, and B estimated by the gradient-wind equilibrium assumption), was determined for three cases of typhoons making landfall in Japan in recent years. As a result, it was confirmed that the proposed equations for parameter B are the most accurate amongst the three estimation methods. Accordingly, the improvement in the accuracy of the ETM using the estimation equations was validated. When using the ETM in the future, high accuracy can be realized by utilizing the estimation equations used in this study.
{"title":"Optimization of empirical typhoon model considering the difference of radius between pressure gradient and wind speed distributions","authors":"M. Toyoda, N. Mori, J. Yoshino","doi":"10.1080/21664250.2022.2035514","DOIUrl":"https://doi.org/10.1080/21664250.2022.2035514","url":null,"abstract":"ABSTRACT This study proposes empirical relations for the ratio of the radius of maximum pressure gradient to the radius of maximum wind speed for the empirical typhoon model (ETM) based on the results of analysis of multiple typhoons obtained from the meteorological model. One proposed relation was parameterized based on the attenuation rate from the peak time to landfall time. The other was parameterized based on the distance from where the typhoon reached its peak intensity to the coastline. These relationships are useful for practical applications. In addition, the typhoon pressure shape parameter B was calculated from the constructed equations and the relational equation proposed by Holland. The improvement in accuracy, as compared with conventional ETM (B = 1, and B estimated by the gradient-wind equilibrium assumption), was determined for three cases of typhoons making landfall in Japan in recent years. As a result, it was confirmed that the proposed equations for parameter B are the most accurate amongst the three estimation methods. Accordingly, the improvement in the accuracy of the ETM using the estimation equations was validated. When using the ETM in the future, high accuracy can be realized by utilizing the estimation equations used in this study.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"376 - 386"},"PeriodicalIF":2.4,"publicationDate":"2022-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43284782","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 : 2022-01-02DOI: 10.1080/21664250.2022.2027090
Naoto Inagaki, T. Shibayama, T. Takabatake, M. Esteban, Martin Mäll, Thit Oo Kyaw
ABSTRACT A field survey of Fukuura Coast (in Tokyo Bay, Japan) revealed during the passage of Typhoon Faxai in 2019 waves with considerable momentum caused significant wave overtopping, resulting in structural damage to coastal defenses and localized flooding. The hindcasted wave height using a third-generation wave model was not high enough to explain the extent of the local damage at Fukuura Coast, likely due to such methods failing to take into account the strong gust-winds recorded during the passage of the typhoon. To solve such problems the authors developed a new numerical model that takes into account the dynamic interaction of air and water, based on the finite volume method (FVM) and the volume of fluid method (VOF). Although this model still slightly underestimates the measurements in the experiments previously conducted by different authors, it is better than existing methods when estimating the overtopping rates under strong winds. The model was then applied to a real-scale model of Fukuura Coast, where by taking into account strong gust-wind speed of 41 m/s the authors were able to explain the phenomena that took place.
{"title":"Increase in overtopping rate caused by local gust-winds during the passage of a typhoon","authors":"Naoto Inagaki, T. Shibayama, T. Takabatake, M. Esteban, Martin Mäll, Thit Oo Kyaw","doi":"10.1080/21664250.2022.2027090","DOIUrl":"https://doi.org/10.1080/21664250.2022.2027090","url":null,"abstract":"ABSTRACT A field survey of Fukuura Coast (in Tokyo Bay, Japan) revealed during the passage of Typhoon Faxai in 2019 waves with considerable momentum caused significant wave overtopping, resulting in structural damage to coastal defenses and localized flooding. The hindcasted wave height using a third-generation wave model was not high enough to explain the extent of the local damage at Fukuura Coast, likely due to such methods failing to take into account the strong gust-winds recorded during the passage of the typhoon. To solve such problems the authors developed a new numerical model that takes into account the dynamic interaction of air and water, based on the finite volume method (FVM) and the volume of fluid method (VOF). Although this model still slightly underestimates the measurements in the experiments previously conducted by different authors, it is better than existing methods when estimating the overtopping rates under strong winds. The model was then applied to a real-scale model of Fukuura Coast, where by taking into account strong gust-wind speed of 41 m/s the authors were able to explain the phenomena that took place.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"116 - 134"},"PeriodicalIF":2.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47137256","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 : 2022-01-02DOI: 10.1080/21664250.2021.2023380
Clemens Krautwald, H. Von Häfen, P. Niebuhr, K. Vögele, D. Schürenkamp, M. Sieder, N. Goseberg
ABSTRACT Amongst extreme hydrodynamic events are bore- and surge-type flow motions that are observed in the context of storm surges induced by tropical cyclones, but also occur when tsunami or flash floods strike. Coastal houses built on elevated pile foundations have suffered less damages in recent extreme hydrodynamic events since the water could pass beneath the floor slabs decreasing the exertion of forces onto structures. To date, research pertaining to horizontal and vertical forces on elevated structures is still scarce. Specifically, previous research may not be applicable to cases of bore-type inundation interacting with elevated coastal structures. This work hence aims to model non-elevated and elevated coastal structure, and to deepen insight into forces with a focus on the structural elevation. For this purpose, large-scale experimental tests were performed on a uniform 1:15 slope in combination with an adjacent horizontal plane. Idealized residential buildings on a length scale of 1:5 were designed to simulate loading conditions of broken solitary waves on slab-on-grade and elevated buildings. A wide range of horizontal forces between 0.1 and 10 , vertical forces between 0.5 and 7.5 and overturning moments up to 4.5 were measured. In accordance with the experimental results, design equations were derived.
{"title":"Large-scale physical modeling of broken solitary waves impacting elevated coastal structures","authors":"Clemens Krautwald, H. Von Häfen, P. Niebuhr, K. Vögele, D. Schürenkamp, M. Sieder, N. Goseberg","doi":"10.1080/21664250.2021.2023380","DOIUrl":"https://doi.org/10.1080/21664250.2021.2023380","url":null,"abstract":"ABSTRACT Amongst extreme hydrodynamic events are bore- and surge-type flow motions that are observed in the context of storm surges induced by tropical cyclones, but also occur when tsunami or flash floods strike. Coastal houses built on elevated pile foundations have suffered less damages in recent extreme hydrodynamic events since the water could pass beneath the floor slabs decreasing the exertion of forces onto structures. To date, research pertaining to horizontal and vertical forces on elevated structures is still scarce. Specifically, previous research may not be applicable to cases of bore-type inundation interacting with elevated coastal structures. This work hence aims to model non-elevated and elevated coastal structure, and to deepen insight into forces with a focus on the structural elevation. For this purpose, large-scale experimental tests were performed on a uniform 1:15 slope in combination with an adjacent horizontal plane. Idealized residential buildings on a length scale of 1:5 were designed to simulate loading conditions of broken solitary waves on slab-on-grade and elevated buildings. A wide range of horizontal forces between 0.1 and 10 , vertical forces between 0.5 and 7.5 and overturning moments up to 4.5 were measured. In accordance with the experimental results, design equations were derived.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"169 - 189"},"PeriodicalIF":2.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47992519","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 : 2022-01-02DOI: 10.1080/21664250.2022.2046758
Y. Tajima, A. Kennedy
Prevention and mitigation of coastal disasters is one of most essential tasks of coastal engineers. In previous issues, Coastal Engineering Journal has published a number of articles which focus on the postdisaster survey of catastrophic events induced by intensive tropical cyclones, as shown in Table 1 and Figure 1. This special issue focuses on analysis and investigations of these recent events to deepen understanding of coastal hazards and risks and to improve disaster prevention and mitigation measures. This special issue has 11 articles, which present: (i) Survey reports; (ii) Numerical investigations of the physical mechanisms and characteristics of reported events; (iii) Laboratory experiments on hydrodynamic force acting on structures; and (iv) Future projection of typhoon-induced coastal hazards. In addition to detailed ground survey data and satellite-based comprehensive and panoramic information, recent events often have onsite videos taken by local residents. Archives of these data are essential to understand and mitigate coastal hazards and risks and for development of future protection and mitigation strategies. As guest editors, we are pleased if this special issue contributes to bringing attention to these archives of recent survey data and their findings.
{"title":"Special issue on coastal hazards and risks due to tropical cyclones","authors":"Y. Tajima, A. Kennedy","doi":"10.1080/21664250.2022.2046758","DOIUrl":"https://doi.org/10.1080/21664250.2022.2046758","url":null,"abstract":"Prevention and mitigation of coastal disasters is one of most essential tasks of coastal engineers. In previous issues, Coastal Engineering Journal has published a number of articles which focus on the postdisaster survey of catastrophic events induced by intensive tropical cyclones, as shown in Table 1 and Figure 1. This special issue focuses on analysis and investigations of these recent events to deepen understanding of coastal hazards and risks and to improve disaster prevention and mitigation measures. This special issue has 11 articles, which present: (i) Survey reports; (ii) Numerical investigations of the physical mechanisms and characteristics of reported events; (iii) Laboratory experiments on hydrodynamic force acting on structures; and (iv) Future projection of typhoon-induced coastal hazards. In addition to detailed ground survey data and satellite-based comprehensive and panoramic information, recent events often have onsite videos taken by local residents. Archives of these data are essential to understand and mitigate coastal hazards and risks and for development of future protection and mitigation strategies. As guest editors, we are pleased if this special issue contributes to bringing attention to these archives of recent survey data and their findings.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"1 - 2"},"PeriodicalIF":2.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49357104","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 : 2022-01-02DOI: 10.1080/21664250.2021.2017191
M. Takagi, J. Ninomiya, N. Mori, T. Shimura, T. Miyashita
ABSTRACT The parameterization of the sea surface turbulent kinetic energy (TKE) flux due to wave breaking was revisited using the observed data. It is found that the fraction of wave energy taken up into the ocean as sea surface TKE flux depends on the relative angle between wind and wave direction. The fraction tends to be larger under opposite wind conditions than following wind conditions. Based on the observed results, a new parameterization of TKE flux was proposed. The TKE flux parameterization was implemented into the atmosphere-ocean-wave coupled model. The experiments on typhoon hindcast using the model showed that TKE flux affects weak mixing at the ocean surface, strong mixing at the bottom of the mixed layer, and near-inertial internal waves depending on the thickness of the mixed layer depth (MLD). In the coupled atmosphere-ocean-wave model, the effects of these mixing differences are also fed back to the atmospheric side; the maximum difference in the central pressure of the typhoon depending on TKE flux parameterization is 10 hPa. The results of this study suggest the importance of considering waves in the sea surface TKE flux for typhoon simulations.
{"title":"Impacts of wave-induced ocean surface turbulent kinetic energy flux on typhoon characteristics","authors":"M. Takagi, J. Ninomiya, N. Mori, T. Shimura, T. Miyashita","doi":"10.1080/21664250.2021.2017191","DOIUrl":"https://doi.org/10.1080/21664250.2021.2017191","url":null,"abstract":"ABSTRACT The parameterization of the sea surface turbulent kinetic energy (TKE) flux due to wave breaking was revisited using the observed data. It is found that the fraction of wave energy taken up into the ocean as sea surface TKE flux depends on the relative angle between wind and wave direction. The fraction tends to be larger under opposite wind conditions than following wind conditions. Based on the observed results, a new parameterization of TKE flux was proposed. The TKE flux parameterization was implemented into the atmosphere-ocean-wave coupled model. The experiments on typhoon hindcast using the model showed that TKE flux affects weak mixing at the ocean surface, strong mixing at the bottom of the mixed layer, and near-inertial internal waves depending on the thickness of the mixed layer depth (MLD). In the coupled atmosphere-ocean-wave model, the effects of these mixing differences are also fed back to the atmospheric side; the maximum difference in the central pressure of the typhoon depending on TKE flux parameterization is 10 hPa. The results of this study suggest the importance of considering waves in the sea surface TKE flux for typhoon simulations.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"151 - 168"},"PeriodicalIF":2.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46736768","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 : 2022-01-02DOI: 10.1080/21664250.2021.2002060
M. Toyoda, J. Yoshino, Tomonao Kobayashi
ABSTRACT In this study, dynamical pseudo-global-warming downscaling (d-PGWD) was performed with a high-resolution typhoon model for 49 typhoons that made landfall in Japan between 2000 and 2017. It was revealed that the averaged typhoon intensity under future climatic conditions tends to increase at both the peak and landfall times as a result of global warming (averaged central pressures of −45.7 and −5.5 hPa at peak and landfall, respectively). Furthermore, detailed analyses of the time of landfall revealed significant differences in the degree of future changes in typhoon intensity based on both the elapsed time from the genesis to landfall (Tl ) and the radius of maximum wind speed (Rml ) at the time of landfall. Considering the relationships of Tl and Rml between present and future climates, statistical formulas for future changes in the central pressure and Rml were derived as an empirical PGWD (e-PGWD) method. The validity of this method was confirmed via comparison with d-PGWD results. It is expected that disaster prevention and mitigation measures for future typhoons and coastal disasters in individual regions and ports can be developed by revising storm surge hazard maps using the proposed e-PGWD approach.
{"title":"Future changes in typhoons and storm surges along the Pacific coast in Japan: proposal of an empirical pseudo-global-warming downscaling","authors":"M. Toyoda, J. Yoshino, Tomonao Kobayashi","doi":"10.1080/21664250.2021.2002060","DOIUrl":"https://doi.org/10.1080/21664250.2021.2002060","url":null,"abstract":"ABSTRACT In this study, dynamical pseudo-global-warming downscaling (d-PGWD) was performed with a high-resolution typhoon model for 49 typhoons that made landfall in Japan between 2000 and 2017. It was revealed that the averaged typhoon intensity under future climatic conditions tends to increase at both the peak and landfall times as a result of global warming (averaged central pressures of −45.7 and −5.5 hPa at peak and landfall, respectively). Furthermore, detailed analyses of the time of landfall revealed significant differences in the degree of future changes in typhoon intensity based on both the elapsed time from the genesis to landfall (Tl ) and the radius of maximum wind speed (Rml ) at the time of landfall. Considering the relationships of Tl and Rml between present and future climates, statistical formulas for future changes in the central pressure and Rml were derived as an empirical PGWD (e-PGWD) method. The validity of this method was confirmed via comparison with d-PGWD results. It is expected that disaster prevention and mitigation measures for future typhoons and coastal disasters in individual regions and ports can be developed by revising storm surge hazard maps using the proposed e-PGWD approach.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"190 - 215"},"PeriodicalIF":2.4,"publicationDate":"2022-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45796715","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 : 2021-12-29DOI: 10.1080/21664250.2021.2015199
T. Kakinuma, Y. Kusuhara
ABSTRACT Three-dimensional numerical simulations were generated for tsunamis ascending processes with different river topographies. As tsunamis propagated in a narrow river, the radius of curvature around the first wave peak decreased, increasing the tsunami height with wave disintegration until the second tsunami height peak appeared. The diffracted waves also entered the river channel, causing an increase in tsunami height in the vicinity of the riverbank at the estuary. The tsunami height increased in a uniform riverbed gradient and narrower river width toward the upstream, based on the shallowing and energy concentration. As the angle between the riverbank line and coastline at the estuary was acute, the tsunami height was reduced because the diffracted waves were difficult to enter the river. The tsunami height in the rivers increased as the ratio of representative wavelength to river width was increased. The maximum tsunami height in the bore-shaped wave was larger than in the solitary wave with the same incident wave height. In the case of tsunami propagation in the compound cross-section river, multiple crestlines appeared because the tsunamis traveling diagonally in the flood channel showed multiple reflections both on the riverbank and between the flood and main channels.
{"title":"A 3D numerical study on tsunamis ascending a river","authors":"T. Kakinuma, Y. Kusuhara","doi":"10.1080/21664250.2021.2015199","DOIUrl":"https://doi.org/10.1080/21664250.2021.2015199","url":null,"abstract":"ABSTRACT Three-dimensional numerical simulations were generated for tsunamis ascending processes with different river topographies. As tsunamis propagated in a narrow river, the radius of curvature around the first wave peak decreased, increasing the tsunami height with wave disintegration until the second tsunami height peak appeared. The diffracted waves also entered the river channel, causing an increase in tsunami height in the vicinity of the riverbank at the estuary. The tsunami height increased in a uniform riverbed gradient and narrower river width toward the upstream, based on the shallowing and energy concentration. As the angle between the riverbank line and coastline at the estuary was acute, the tsunami height was reduced because the diffracted waves were difficult to enter the river. The tsunami height in the rivers increased as the ratio of representative wavelength to river width was increased. The maximum tsunami height in the bore-shaped wave was larger than in the solitary wave with the same incident wave height. In the case of tsunami propagation in the compound cross-section river, multiple crestlines appeared because the tsunamis traveling diagonally in the flood channel showed multiple reflections both on the riverbank and between the flood and main channels.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"272 - 284"},"PeriodicalIF":2.4,"publicationDate":"2021-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43000080","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 : 2021-12-07DOI: 10.1080/21664250.2021.1991730
Y. Shigihara, K. Imai, H. Iwase, K. Kawasaki, M. Nemoto, T. Baba, N. Chikasada, Y. Chida, T. Arikawa
ABSTRACT Researchers have developed tsunami inundation models based on nonlinear shallow water equations to estimate tsunami propagation and inundation. However, their empirical results are not in perfect agreement with those of other research institutes, even though the same governing equations are used. Therefore, we quantitatively evaluated the variability of tsunami simulations in this study. Several research institutes have conducted tsunami simulations under the same input conditions using tsunami inundation models adopted for tsunami hazard assessment, resulting in a certain degree of variability among them. By examining the spatial and temporal differences in various physical quantities, we identified the characteristic topography where the variability between tsunami simulations increases. A novel method for calculating statistics from the area integrals of physical quantities was proposed to demonstrate the variability in the overall simulation results. In addition, the effects of different setting parameters and computational environments on the simulation results of a single model were evaluated. The findings of this study are expected to not only serve as a basis to verify the reliability of source codes employed by users of the tsunami inundation model, but also contribute useful technical information to advance probabilistic tsunami hazard assessment in the future.
{"title":"Variation analysis of multiple tsunami inundation models","authors":"Y. Shigihara, K. Imai, H. Iwase, K. Kawasaki, M. Nemoto, T. Baba, N. Chikasada, Y. Chida, T. Arikawa","doi":"10.1080/21664250.2021.1991730","DOIUrl":"https://doi.org/10.1080/21664250.2021.1991730","url":null,"abstract":"ABSTRACT Researchers have developed tsunami inundation models based on nonlinear shallow water equations to estimate tsunami propagation and inundation. However, their empirical results are not in perfect agreement with those of other research institutes, even though the same governing equations are used. Therefore, we quantitatively evaluated the variability of tsunami simulations in this study. Several research institutes have conducted tsunami simulations under the same input conditions using tsunami inundation models adopted for tsunami hazard assessment, resulting in a certain degree of variability among them. By examining the spatial and temporal differences in various physical quantities, we identified the characteristic topography where the variability between tsunami simulations increases. A novel method for calculating statistics from the area integrals of physical quantities was proposed to demonstrate the variability in the overall simulation results. In addition, the effects of different setting parameters and computational environments on the simulation results of a single model were evaluated. The findings of this study are expected to not only serve as a basis to verify the reliability of source codes employed by users of the tsunami inundation model, but also contribute useful technical information to advance probabilistic tsunami hazard assessment in the future.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":"64 1","pages":"344 - 371"},"PeriodicalIF":2.4,"publicationDate":"2021-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43630792","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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