Pub Date : 2022-07-03DOI: 10.1080/21664250.2022.2116775
Shota Okura, S. Hosokawa
ABSTRACT The sea surface temperature estimated by satellites (SSTskin) may facilitate the understanding of processes that affect water quality in semi-enclosed bays. However, the representativeness and certainty of SSTskin in semi-enclosed bays have not been fully investigated. We investigated the SSTskin from MODIS in Tokyo Bay and Ise Bay to test the hypothesis that water-mass structure and proximity to land would affect SSTskin. Results showed that the SSTskin from MODIS in two semi-enclosed bays can be as representative and certain as the data from previous studies in the open ocean. We found that horizontal gradients of water temperature had little effect on the certainty of SSTskin. However, we found that both the representativeness and certainty of satellite-based estimates of SSTskin in semi-enclosed bays were reduced by seasonal and location characteristics. The representativeness and certainty of SSTskin near the mouth of Ise Bay were compromised by the complex vertical structure of water temperature in summer. Because SSTskin may greatly enhance understanding of the processes that affect water quality in semi-enclosed bays, our results indicate that prior validation of SSTskin by comparison with in-situ sea surface temperature (SSTdep) is important.
{"title":"Representativeness and certainty of sea surface temperature from MODIS in semi-enclosed bays","authors":"Shota Okura, S. Hosokawa","doi":"10.1080/21664250.2022.2116775","DOIUrl":"https://doi.org/10.1080/21664250.2022.2116775","url":null,"abstract":"ABSTRACT The sea surface temperature estimated by satellites (SSTskin) may facilitate the understanding of processes that affect water quality in semi-enclosed bays. However, the representativeness and certainty of SSTskin in semi-enclosed bays have not been fully investigated. We investigated the SSTskin from MODIS in Tokyo Bay and Ise Bay to test the hypothesis that water-mass structure and proximity to land would affect SSTskin. Results showed that the SSTskin from MODIS in two semi-enclosed bays can be as representative and certain as the data from previous studies in the open ocean. We found that horizontal gradients of water temperature had little effect on the certainty of SSTskin. However, we found that both the representativeness and certainty of satellite-based estimates of SSTskin in semi-enclosed bays were reduced by seasonal and location characteristics. The representativeness and certainty of SSTskin near the mouth of Ise Bay were compromised by the complex vertical structure of water temperature in summer. Because SSTskin may greatly enhance understanding of the processes that affect water quality in semi-enclosed bays, our results indicate that prior validation of SSTskin by comparison with in-situ sea surface temperature (SSTdep) is important.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43615272","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}
ABSTRACT As the lower boundary of suspended particles, the critical condition of suspension is an important component in the theory of nonuniform sediment transport and plays a significant role in the numerical computations in the suspended sediment movement. Previous studies on critical suspension are mostly based on Rouse number and Shields number. From the perspective of maximum particle size, this paper conducted research on the critical suspension of nonuniform sediment by flume experiment. A new criterion for critical suspension of nonuniform sediment is proposed according to the concept of maximum particle Reynolds number and analysis of experimental data. Sediments will not be suspended unless the particle Reynolds number is less than or equal to the maximum one related to flow and boundary conditions. A formula, established from experimental data, indicates that the maximum particle Reynolds number is proportional to 3 power of Froude number and 1/5 power of relative roughness. As a new criterion for critical suspension, this formula offers a reasonable description of the physical mechanism for the initial movement of the suspended load. Not only does the proposed formula agree well with laboratory and field data, but it also has its advantages compared with traditional criteria.
{"title":"A new criterion for critical suspension of nonuniform sediment","authors":"Zhi-lin Sun, Yun Gao, Lixia Sun, Haolei Zheng, Wengang Xiang, Yimeng Gao","doi":"10.1080/21664250.2022.2120584","DOIUrl":"https://doi.org/10.1080/21664250.2022.2120584","url":null,"abstract":"ABSTRACT As the lower boundary of suspended particles, the critical condition of suspension is an important component in the theory of nonuniform sediment transport and plays a significant role in the numerical computations in the suspended sediment movement. Previous studies on critical suspension are mostly based on Rouse number and Shields number. From the perspective of maximum particle size, this paper conducted research on the critical suspension of nonuniform sediment by flume experiment. A new criterion for critical suspension of nonuniform sediment is proposed according to the concept of maximum particle Reynolds number and analysis of experimental data. Sediments will not be suspended unless the particle Reynolds number is less than or equal to the maximum one related to flow and boundary conditions. A formula, established from experimental data, indicates that the maximum particle Reynolds number is proportional to 3 power of Froude number and 1/5 power of relative roughness. As a new criterion for critical suspension, this formula offers a reasonable description of the physical mechanism for the initial movement of the suspended load. Not only does the proposed formula agree well with laboratory and field data, but it also has its advantages compared with traditional criteria.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44126179","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 : 2022-07-03DOI: 10.1080/21664250.2022.2118431
Daisuke Kobayashi, T. Uchida
ABSTRACT This study investigates the propagation characteristics of breaking bore in meandering channels focusing on the effects of Froude number (F) on the breaking bore. The experiments are conducted with different Froude number conditions of F = 3.99 for high F and F = 1.53 for low F in a straight and meandering channel. The experimental results are compared with calculated results by Shallow Water Equation (SWE) model and three-dimensional calculation model. In the low F condition, the oscillation of water level like a soliton fission was observed and it was amplified along both banks in the meandering channel. This was explained using the temporal variation of the transverse water surface gradient calculated by SWE model, that is not related with non-hydrostatic pressure component and vertical distribution of the velocity. The high F condition is characterized by the longitudinal gradient of bore head caused by large energy loss. In the meandering channel, the SWE model overestimated the wave height near the bore front along both banks. This is because the secondary flow in the meandering channel increases the velocity near the bed and the flow resistance compared with low F condition and reduces the wave height.
{"title":"Experimental and numerical investigation of breaking bores in straight and meandering channels with different Froude numbers","authors":"Daisuke Kobayashi, T. Uchida","doi":"10.1080/21664250.2022.2118431","DOIUrl":"https://doi.org/10.1080/21664250.2022.2118431","url":null,"abstract":"ABSTRACT This study investigates the propagation characteristics of breaking bore in meandering channels focusing on the effects of Froude number (F) on the breaking bore. The experiments are conducted with different Froude number conditions of F = 3.99 for high F and F = 1.53 for low F in a straight and meandering channel. The experimental results are compared with calculated results by Shallow Water Equation (SWE) model and three-dimensional calculation model. In the low F condition, the oscillation of water level like a soliton fission was observed and it was amplified along both banks in the meandering channel. This was explained using the temporal variation of the transverse water surface gradient calculated by SWE model, that is not related with non-hydrostatic pressure component and vertical distribution of the velocity. The high F condition is characterized by the longitudinal gradient of bore head caused by large energy loss. In the meandering channel, the SWE model overestimated the wave height near the bore front along both banks. This is because the secondary flow in the meandering channel increases the velocity near the bed and the flow resistance compared with low F condition and reduces the wave height.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42930430","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 : 2022-06-25DOI: 10.1080/21664250.2022.2088194
P. Winckler, César Esparza, J. Mora, O. Melo, N. Bambach, M. Contreras-López, M. Sactic
ABSTRACT Economic costs due to operational downtime and wave overtopping under the RCP 8.5 scenario are evaluated at 7 Chilean ports. Wave statistics for a historical period (1985–2004), mid-century (2026–2045), and end-of-century projections (2081–2100) are computed with a Pacific-wide model, forced by wind fields from six General Circulation Models. Offshore waves are then downscaled to each port, where a proxy of downtime is computed by comparing wave heights with vessel berthing criteria. The difference in downtime between the historical and future projections is attributed to climate change. Results show that some ports would reduce and others increase downtime for mid-century projections due to local effects. However, by the end-of-century, all ports would experience a reduction in downtime. Additionally, by mid-century, overtopping would increase in northern ports as a combination of extreme waves and sea-level rise (SLR), while in southern ports, it is expected to be slightly reduced. By the end-of century, overtopping would increase in the whole region, mainly driven by SLR. However, overtopping is significantly altered by coseismic uplift/subsidence that may occur during the design-life of coastal works. Finally, a few practical suggestions aimed atimproving infrastructure management and operational conditions at the analyzed ports are outlined.
{"title":"Impacts in ports on a tectonically active coast for climate-driven projections under the RCP 8.5 scenario: 7 Chilean ports under scrutiny","authors":"P. Winckler, César Esparza, J. Mora, O. Melo, N. Bambach, M. Contreras-López, M. Sactic","doi":"10.1080/21664250.2022.2088194","DOIUrl":"https://doi.org/10.1080/21664250.2022.2088194","url":null,"abstract":"ABSTRACT Economic costs due to operational downtime and wave overtopping under the RCP 8.5 scenario are evaluated at 7 Chilean ports. Wave statistics for a historical period (1985–2004), mid-century (2026–2045), and end-of-century projections (2081–2100) are computed with a Pacific-wide model, forced by wind fields from six General Circulation Models. Offshore waves are then downscaled to each port, where a proxy of downtime is computed by comparing wave heights with vessel berthing criteria. The difference in downtime between the historical and future projections is attributed to climate change. Results show that some ports would reduce and others increase downtime for mid-century projections due to local effects. However, by the end-of-century, all ports would experience a reduction in downtime. Additionally, by mid-century, overtopping would increase in northern ports as a combination of extreme waves and sea-level rise (SLR), while in southern ports, it is expected to be slightly reduced. By the end-of century, overtopping would increase in the whole region, mainly driven by SLR. However, overtopping is significantly altered by coseismic uplift/subsidence that may occur during the design-life of coastal works. Finally, a few practical suggestions aimed atimproving infrastructure management and operational conditions at the analyzed ports are outlined.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2022-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41440463","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 : 2022-06-25DOI: 10.1080/21664250.2022.2089445
Paterno S. Miranda, N. Kobayashi
ABSTRACT The erosional and accretional profile changes of an intertidal mudflat are examined using available field data and the cross-shore numerical model CSHORE that is extended to allow for a mixture of sand and mud. The semidiurnal migration of the still water shoreline and surf zone is resolved numerically to predict the net cross-shore and longshore sediment transport rates influenced by the small cross-shore (undertow) and longshore currents induced by breaking waves of about 0.2 m height. Alongshore sediment loss or gain is included by approximating the alongshore sediment transport gradient using an equivalent alongshore length. The calibrated CSHORE reproduces the measured erosional (accretional) profile change of about 0.1 m (0.1 m) over a cross-shore distance of 950 m during the erosional (accretional) interval of 206 (195) days. The mudflat profile changes are equally affected by mud characteristics, the semidiurnal tide amplitude, and the wave height, period, and direction. In addition, the alongshore water level gradient and wind stress influence longshore current and sediment transport. This study shows the importance of sediment transport in the surf zone that may have been excluded in previous numerical modeling.
{"title":"Numerical modeling of intertidal mudflat profile evolution under waves and currents","authors":"Paterno S. Miranda, N. Kobayashi","doi":"10.1080/21664250.2022.2089445","DOIUrl":"https://doi.org/10.1080/21664250.2022.2089445","url":null,"abstract":"ABSTRACT The erosional and accretional profile changes of an intertidal mudflat are examined using available field data and the cross-shore numerical model CSHORE that is extended to allow for a mixture of sand and mud. The semidiurnal migration of the still water shoreline and surf zone is resolved numerically to predict the net cross-shore and longshore sediment transport rates influenced by the small cross-shore (undertow) and longshore currents induced by breaking waves of about 0.2 m height. Alongshore sediment loss or gain is included by approximating the alongshore sediment transport gradient using an equivalent alongshore length. The calibrated CSHORE reproduces the measured erosional (accretional) profile change of about 0.1 m (0.1 m) over a cross-shore distance of 950 m during the erosional (accretional) interval of 206 (195) days. The mudflat profile changes are equally affected by mud characteristics, the semidiurnal tide amplitude, and the wave height, period, and direction. In addition, the alongshore water level gradient and wind stress influence longshore current and sediment transport. This study shows the importance of sediment transport in the surf zone that may have been excluded in previous numerical modeling.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2022-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42853285","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 : 2022-05-17DOI: 10.1080/21664250.2022.2073748
Q. Nguyen Hao, S. Takewaka
ABSTRACT Hai Hau, located in northern Vietnam, has suffered from severe coastal erosion with a retreat rate reaching 20 m/yr in recent years. Based on a systematic review of the literature, the shoreline recession trend along the Hai Hau is associated with the decline of water and sediment discharged from the So River, assumed to be active after a great flood in 1787, resulting in channel bifurcation and abandonment of the former channel. A historical analysis of the shoreline evolution of approximately a thousand years (the year 1000 – present) was conducted along this scenario using a modified one-line model. The simulated shorelines agreed well with the results of carbon-14 dating analysis, the historical reference points and shoreline positions extracted from the old maps, and the recently measured shoreline change derived from Landsat imagery. The present study demonstrates that the erosion at the Hai Hau has been ongoing from the end of the 18th century rather than the beginning of the 20th century, as proposed by some previous works. We regard the combined effects of the decrease in river sediment load, and other processes (subsidence and sea level rise (SLR)) are the major causes of long-term erosion on Hai Hau Coast.
{"title":"Historical reconstruction of shoreline evolution at the Nam Dinh Coast, Vietnam","authors":"Q. Nguyen Hao, S. Takewaka","doi":"10.1080/21664250.2022.2073748","DOIUrl":"https://doi.org/10.1080/21664250.2022.2073748","url":null,"abstract":"ABSTRACT Hai Hau, located in northern Vietnam, has suffered from severe coastal erosion with a retreat rate reaching 20 m/yr in recent years. Based on a systematic review of the literature, the shoreline recession trend along the Hai Hau is associated with the decline of water and sediment discharged from the So River, assumed to be active after a great flood in 1787, resulting in channel bifurcation and abandonment of the former channel. A historical analysis of the shoreline evolution of approximately a thousand years (the year 1000 – present) was conducted along this scenario using a modified one-line model. The simulated shorelines agreed well with the results of carbon-14 dating analysis, the historical reference points and shoreline positions extracted from the old maps, and the recently measured shoreline change derived from Landsat imagery. The present study demonstrates that the erosion at the Hai Hau has been ongoing from the end of the 18th century rather than the beginning of the 20th century, as proposed by some previous works. We regard the combined effects of the decrease in river sediment load, and other processes (subsidence and sea level rise (SLR)) are the major causes of long-term erosion on Hai Hau Coast.","PeriodicalId":50673,"journal":{"name":"Coastal Engineering Journal","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2022-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44847482","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: 10.1080/21664250.2022.2072611
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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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}
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