Pub Date : 2022-01-30DOI: 10.20481/kscdp.2022.9.1.75
Yonghyun Cho, S. Cho
This study aims to develop an amendment to the design guidelines for the outer port facilities based on quantitative indexes to address harsh wave conditions due to climate change. To this end, the author first looked into the in situ data of damage to outer port facilities collected in about a dozen major ports in Korea, where the outer port facility has failed in fulfilling its intended disaster prevention against typhoons over the last decade. In doing so, the design fidelity index, a quantitative index that can rationally determine the scope of reinforcement of outer port facilities, was developed based on the specified failure mechanism. The design fidelity index evaluates the degree of loss of armoring rocks, erosion of main body of breakwater, displacement of cap-concrete, lee side damage by overtopping, and scouring near the toe, which are the primary failure mode of the outer port facilities, and displays these damage extents of each of 5 primary failure mode in polar coordinates. Among the various failure modes mentioned above, scouring near the toe has been found in most outer port facilities, and as a result, the current design practice like whether to install scouring-prevention work is determined based on the limit depth for the incipient sediment motion needs to be revised. Numerical simulation shows that with sediment motion triggered by harsh water surface displacement in the standing waves formed in front of vertical type breakwater being accounted for, the robustness of scouring prevention works, which takes the maximum scour depth as the maximum wave height, could be secured. In addition, among the various quantitative indexes that can provide information concerned with how robust or vulnerable the outer port facilities would be by adjusting design waves return period, it turns out that the increasing rate of failure probability associated with the unit change in the nominal diameter of armoring rocks could provide most promising results.
{"title":"Preliminary Study on an amendment to the Design Guideline of Outer Port Facilities Against Harsh Wave Conditions due to Climate Change based on Design Fidelity Index","authors":"Yonghyun Cho, S. Cho","doi":"10.20481/kscdp.2022.9.1.75","DOIUrl":"https://doi.org/10.20481/kscdp.2022.9.1.75","url":null,"abstract":"This study aims to develop an amendment to the design guidelines for the outer port facilities based on quantitative indexes to address harsh wave conditions due to climate change. To this end, the author first looked into the in situ data of damage to outer port facilities collected in about a dozen major ports in Korea, where the outer port facility has failed in fulfilling its intended disaster prevention against typhoons over the last decade. In doing so, the design fidelity index, a quantitative index that can rationally determine the scope of reinforcement of outer port facilities, was developed based on the specified failure mechanism. The design fidelity index evaluates the degree of loss of armoring rocks, erosion of main body of breakwater, displacement of cap-concrete, lee side damage by overtopping, and scouring near the toe, which are the primary failure mode of the outer port facilities, and displays these damage extents of each of 5 primary failure mode in polar coordinates. Among the various failure modes mentioned above, scouring near the toe has been found in most outer port facilities, and as a result, the current design practice like whether to install scouring-prevention work is determined based on the limit depth for the incipient sediment motion needs to be revised. Numerical simulation shows that with sediment motion triggered by harsh water surface displacement in the standing waves formed in front of vertical type breakwater being accounted for, the robustness of scouring prevention works, which takes the maximum scour depth as the maximum wave height, could be secured. In addition, among the various quantitative indexes that can provide information concerned with how robust or vulnerable the outer port facilities would be by adjusting design waves return period, it turns out that the increasing rate of failure probability associated with the unit change in the nominal diameter of armoring rocks could provide most promising results.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134373446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-30DOI: 10.20481/kscdp.2022.9.1.13
Bae-Seong Lee, Min-Kyu Jung, H. Kwon
The Saemangeum Sea Dike, completed in 2011 in South Korea, is the longest sea dike in the world. One of the most pressing issues of today, climate change leads to sea-level rise that could increase the risk of sea dike overflow. However, what impact climate change will have on the Saemangeum Sea Dike has not been verified yet. Here, we estimate the impacts of sea-level rise on the Saemangeum Sea Dike, using the Linear Regression Analysis method, the Continuous Wavelet Transform (CWT) method, and the Ensemble Empirical Mode Decomposition (EEMD) method. The sea level data of the Saemangeum area over the last 30 years were analyzed, and the results showed that the maximum rate of sea-level rise of the Saemangeum Sea Dike is at 2.51 mm/year when the EEMD method was applied. It means that the impact of sea-level rise on the Saemangeum sea dike is reasonably low because the sea level rise will exceed the freeboard after 366 years, so there is currently no clear sign that it poses a problem.
{"title":"Climate Change Impacts of Sea Level Rise on the Saemangeum Sea Dike","authors":"Bae-Seong Lee, Min-Kyu Jung, H. Kwon","doi":"10.20481/kscdp.2022.9.1.13","DOIUrl":"https://doi.org/10.20481/kscdp.2022.9.1.13","url":null,"abstract":"The Saemangeum Sea Dike, completed in 2011 in South Korea, is the longest sea dike in the world. One of the most pressing issues of today, climate change leads to sea-level rise that could increase the risk of sea dike overflow. However, what impact climate change will have on the Saemangeum Sea Dike has not been verified yet. Here, we estimate the impacts of sea-level rise on the Saemangeum Sea Dike, using the Linear Regression Analysis method, the Continuous Wavelet Transform (CWT) method, and the Ensemble Empirical Mode Decomposition (EEMD) method. The sea level data of the Saemangeum area over the last 30 years were analyzed, and the results showed that the maximum rate of sea-level rise of the Saemangeum Sea Dike is at 2.51 mm/year when the EEMD method was applied. It means that the impact of sea-level rise on the Saemangeum sea dike is reasonably low because the sea level rise will exceed the freeboard after 366 years, so there is currently no clear sign that it poses a problem.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133320659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.229
Changkyu Kim, Insik Chun, Byungcheol Oh
An Artificial Intelligence(AI) study was conducted to calculate overtopping discharges for various coastal structures. The Deep Neural Network(DNN), one of the artificial intelligence methods, was employed in the study. The neural network was trained, validated and tested using the EurOtop database containing the experimental data collected from all over the world. To improve the accuracy of the deep neural network results, all data were non-dimensionalized and max-min normalized as a preprocessing process. L2 regularization was also introduced in the cost function to secure the convergence of iterative learning, and the cost function was optimized using RMSProp and Adam techniques. In order to compare the performance of DNN, additional calculations based on the multiple linear regression model and EurOtop’s overtopping formulas were done as well, using the data sets which were not included in the network training. The results showed that the predictive performance of the AI technique was relatively superior to the two other methods.
{"title":"Estimation of Overtopping Discharges with Deep Neural Network(DNN) Method","authors":"Changkyu Kim, Insik Chun, Byungcheol Oh","doi":"10.20481/kscdp.2021.8.4.229","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.229","url":null,"abstract":"An Artificial Intelligence(AI) study was conducted to calculate overtopping discharges for various coastal structures. The Deep Neural Network(DNN), one of the artificial intelligence methods, was employed in the study. The neural network was trained, validated and tested using the EurOtop database containing the experimental data collected from all over the world. To improve the accuracy of the deep neural network results, all data were non-dimensionalized and max-min normalized as a preprocessing process. L2 regularization was also introduced in the cost function to secure the convergence of iterative learning, and the cost function was optimized using RMSProp and Adam techniques. In order to compare the performance of DNN, additional calculations based on the multiple linear regression model and EurOtop’s overtopping formulas were done as well, using the data sets which were not included in the network training. The results showed that the predictive performance of the AI technique was relatively superior to the two other methods.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116326897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.281
Minwoo Kim, Cheolsoo Kim, C. Jang
To project the future sea level rise in the East Asian Seas due to global warming, regional sea level variations are downscaled from three climate system models (GFDL-CM2.1, ECHAM5/MPI-OM, MIROC3.2(hires)) using a global ocean-sea ice coupled model with non-Boussinesq approximation. Based on the SRES A1B Scenario, the projected ensemble mean sea level rise (rate of rise) for the East Sea, Yellow Sea and East China Sea from 1995 to 2050 is 15.60cm (2.84mm/year), 16.49cm (3.0mm/year) and 16.43cm (2.99mm/year), respectively. With the inclusion of the future change of land ice melting and land water storage, the mean sea level rise (rate of rise) increases to 33.55cm (6.10mm/year) for the East Sea, and 34.38~34.44cm (6.25~6.26mm/year) for the Yellow and East China Seas. The present non-Boussinesq ocean model experiment shows that the future sea level rise in the East Sea is mainly due to the steric component changes by heat content increase. On the other hand, the future sea level rise in the Yellow and East China Seas appears to be mainly associated with the non-steric component change by water mass convergence.
{"title":"Projection of future sea level rise in the East Asian Seas based on Global Ocean-Sea Ice Coupled Model with SRES A1B Scenario","authors":"Minwoo Kim, Cheolsoo Kim, C. Jang","doi":"10.20481/kscdp.2021.8.4.281","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.281","url":null,"abstract":"To project the future sea level rise in the East Asian Seas due to global warming, regional sea level variations are downscaled from three climate system models (GFDL-CM2.1, ECHAM5/MPI-OM, MIROC3.2(hires)) using a global ocean-sea ice coupled model with non-Boussinesq approximation. Based on the SRES A1B Scenario, the projected ensemble mean sea level rise (rate of rise) for the East Sea, Yellow Sea and East China Sea from 1995 to 2050 is 15.60cm (2.84mm/year), 16.49cm (3.0mm/year) and 16.43cm (2.99mm/year), respectively. With the inclusion of the future change of land ice melting and land water storage, the mean sea level rise (rate of rise) increases to 33.55cm (6.10mm/year) for the East Sea, and 34.38~34.44cm (6.25~6.26mm/year) for the Yellow and East China Seas. The present non-Boussinesq ocean model experiment shows that the future sea level rise in the East Sea is mainly due to the steric component changes by heat content increase. On the other hand, the future sea level rise in the Yellow and East China Seas appears to be mainly associated with the non-steric component change by water mass convergence.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134122529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.315
Eunju Lee, Sungwon Shin
Predicting tsunami hazards based on the tsunami source, propagation, runup patterns is critical to protect humans and property. Potential tsunami zone, as well as the historical tsunamis in 1983 and 1993, can be a threat to the east coast of South Korea. The Korea Meteorological Administration established a tsunami forecast warning system to reduce damage from tsunamis, but it does not consider tsunami amplification in the bay due to resonance. In this study, the Numerical model, Cornell Multi-grid Coupled Tsunami model, was used to investigate natural frequency in the bay due to coastal geometry. The study area is Yeongill bay in Pohang, southeast of South Korea, because this area is a natural bay and includes three harbors where resonance significantly occurs. This study generated a Gaussian-shaped tsunami, propagated it into the Yeongill bay, and compared numerical modeling results with data from tide gauge located in Yeongill bay during several storms through spectral analysis. It was found that both energies of tsunamis and storms were amplified at the same frequencies, and maximum tsunami wave height was amplified about 3.12 times. The results in this study can contribute to quantifying the amplification of tsunami heights in the bay.
{"title":"Analysis of the tsunami amplification effect by resonance in Yeongil Bay","authors":"Eunju Lee, Sungwon Shin","doi":"10.20481/kscdp.2021.8.4.315","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.315","url":null,"abstract":"Predicting tsunami hazards based on the tsunami source, propagation, runup patterns is critical to protect humans and property. Potential tsunami zone, as well as the historical tsunamis in 1983 and 1993, can be a threat to the east coast of South Korea. The Korea Meteorological Administration established a tsunami forecast warning system to reduce damage from tsunamis, but it does not consider tsunami amplification in the bay due to resonance. In this study, the Numerical model, Cornell Multi-grid Coupled Tsunami model, was used to investigate natural frequency in the bay due to coastal geometry. The study area is Yeongill bay in Pohang, southeast of South Korea, because this area is a natural bay and includes three harbors where resonance significantly occurs. This study generated a Gaussian-shaped tsunami, propagated it into the Yeongill bay, and compared numerical modeling results with data from tide gauge located in Yeongill bay during several storms through spectral analysis. It was found that both energies of tsunamis and storms were amplified at the same frequencies, and maximum tsunami wave height was amplified about 3.12 times. The results in this study can contribute to quantifying the amplification of tsunami heights in the bay.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132812008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.287
H. J. Jung, Young Jun Bang, Seung Oh Lee
As a breakwater gradually becomes obsolete, it becomes vulnerable to loss of its original functions and finally occurs corruption due to cavitation, scours inside, etc. The mortar grouting method, which has been in general applied in many cases, would invoke serious issues such as coastal environmental pollutions because of spilled-out cement before curing on the near sea. Thus, the sand mastic that utilizes the mastic asphalt becomes focused on as a substitute. However, the related study is hard to find in the domestic literature. In this study, therefore, the workability of sand mastic when filling up the cavitation inside a breakwater was evaluated with a 3-D numerical model, FLOW-3D. It was intended to propose the workability index (WI) of sand mastic based on the diffusion diameter. It has been shown that the temperature and the composition ratio of the asphalt are the most significant parameters on the rheologic characteristics of the sand mastic. As a result, it is recommended that the asphalt composition above 16% and the initial temperature above 150℃ when applying with a breakwater with inside cavitation.
{"title":"Numerical simulation for increasing the sand mastic adaptation of repairing the breakwater","authors":"H. J. Jung, Young Jun Bang, Seung Oh Lee","doi":"10.20481/kscdp.2021.8.4.287","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.287","url":null,"abstract":"As a breakwater gradually becomes obsolete, it becomes vulnerable to loss of its original functions and finally occurs corruption due to cavitation, scours inside, etc. The mortar grouting method, which has been in general applied in many cases, would invoke serious issues such as coastal environmental pollutions because of spilled-out cement before curing on the near sea. Thus, the sand mastic that utilizes the mastic asphalt becomes focused on as a substitute. However, the related study is hard to find in the domestic literature. In this study, therefore, the workability of sand mastic when filling up the cavitation inside a breakwater was evaluated with a 3-D numerical model, FLOW-3D. It was intended to propose the workability index (WI) of sand mastic based on the diffusion diameter. It has been shown that the temperature and the composition ratio of the asphalt are the most significant parameters on the rheologic characteristics of the sand mastic. As a result, it is recommended that the asphalt composition above 16% and the initial temperature above 150℃ when applying with a breakwater with inside cavitation.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126215144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.205
C. Shin, D. Gutiérrez
The northern coast of Peru is a region that can rapidly detect the impact of an El Niño. To investigate the effects of the 2015-2016 El Niño on the oceanographic environment of the northern coast of Peru, the temperature and current data obtained from moored equipment at an oil platform were analyzed. Strong coastal along-shore currents of more than 0.60 m·s-1 were observed three times, although the mean current speed was 0.10 m·s-1 flowing toward the south-southwest. After the first strong current, the bottom temperature increased and the mixed layer deepened and remained there during the El Niño event. The temperature reached a maximum after the strong coastal current, then decreased gradually. An analysis of wind and sea surface height anomalies revealed that the coastal strong current was caused by Kelvin waves and the deepening of the mixed layer was not related to local winds, but to coastal Kelvin waves from the equator during the El Niño event.
{"title":"On Abnormally Strong Currents Observed on the Northern Coast of Peru during the 2015-2016 El Niño","authors":"C. Shin, D. Gutiérrez","doi":"10.20481/kscdp.2021.8.4.205","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.205","url":null,"abstract":"The northern coast of Peru is a region that can rapidly detect the impact of an El Niño. To investigate the effects of the 2015-2016 El Niño on the oceanographic environment of the northern coast of Peru, the temperature and current data obtained from moored equipment at an oil platform were analyzed. Strong coastal along-shore currents of more than 0.60 m·s-1 were observed three times, although the mean current speed was 0.10 m·s-1 flowing toward the south-southwest. After the first strong current, the bottom temperature increased and the mixed layer deepened and remained there during the El Niño event. The temperature reached a maximum after the strong coastal current, then decreased gradually. An analysis of wind and sea surface height anomalies revealed that the coastal strong current was caused by Kelvin waves and the deepening of the mixed layer was not related to local winds, but to coastal Kelvin waves from the equator during the El Niño event.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125426849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.267
Seung-Nam Jin, Dong-ha Kim, H. Lim, H. Lee
The Dongsam seawater stream on a reclaimed land flows by tidal forcing. The flow in generally slow, especially in the central portion of the stream because the outflow and inflow each occurs at both ends of the stream simultaneously. As a result, sediments accmulate constantly with the deteorating water quality. In this study, field observation was conducted using Aquadrifter and Aquadopp and analyzed for the analysis of the flow velocity in the stream. The computational fluid dynamics (CFD) modeling was run with and without Seawater Stream Floodgate to predict the variability of the flow. The flow velocity of the Dongsam Seawater Stream was recorded in the range of 0.01 ~ 0.13 m/s, and the tidal range was within 1.0 m. According to the simulation, the flow velocity could increase remarkably with two floodgates used to force the stream to flow unidirectionally (toward Korea Maritime & Ocean University). The flow velocity change rate at each point is recorded -97 ~ 638% at P1 (front of Malfunction Floodgate near Busan Int. Cruise Terminal), -89 ~ 659% at P2 (back of Malfunction Floodgate near Busan Int. Cruise Terminal), -100 ~ 1198% at P3 (central channel), and at P4 (toward Korea Maritime & Ocean University) was -100 to 1163%, and Case III-a showed the largest flow velocity rate increase in the central part. Therefore, if two Floodgates are installed and flowed out toward Korea Maritime & Ocean University, the flow velocity rate of the Stream can be increased.
{"title":"Variability of flow velocity induced by Dongsam Seawater Stream Floodgate installation","authors":"Seung-Nam Jin, Dong-ha Kim, H. Lim, H. Lee","doi":"10.20481/kscdp.2021.8.4.267","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.267","url":null,"abstract":"The Dongsam seawater stream on a reclaimed land flows by tidal forcing. The flow in generally slow, especially in the central portion of the stream because the outflow and inflow each occurs at both ends of the stream simultaneously. As a result, sediments accmulate constantly with the deteorating water quality. In this study, field observation was conducted using Aquadrifter and Aquadopp and analyzed for the analysis of the flow velocity in the stream. The computational fluid dynamics (CFD) modeling was run with and without Seawater Stream Floodgate to predict the variability of the flow. The flow velocity of the Dongsam Seawater Stream was recorded in the range of 0.01 ~ 0.13 m/s, and the tidal range was within 1.0 m. According to the simulation, the flow velocity could increase remarkably with two floodgates used to force the stream to flow unidirectionally (toward Korea Maritime & Ocean University). The flow velocity change rate at each point is recorded -97 ~ 638% at P1 (front of Malfunction Floodgate near Busan Int. Cruise Terminal), -89 ~ 659% at P2 (back of Malfunction Floodgate near Busan Int. Cruise Terminal), -100 ~ 1198% at P3 (central channel), and at P4 (toward Korea Maritime & Ocean University) was -100 to 1163%, and Case III-a showed the largest flow velocity rate increase in the central part. Therefore, if two Floodgates are installed and flowed out toward Korea Maritime & Ocean University, the flow velocity rate of the Stream can be increased.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127913300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.211
Y. Cho
A physics-based morphology model [Seoul Foam] was developed using the dynamic mesh technique to explain the interaction between the sea bed, which undergoes deformation due to siltation and scouring, and the incoming waves. In doing so, OlaFlow, an Open Foam-based toolbox, was used as a hydrodynamic model. To verify the proposed physically-based morphology [Seoul Foam] in this study, numerical simulations of the shoaling process over the beach of the uniform slope were implemented. The numerical result shows that the formation process of a sand bar over the foreshore was successfully simulated. As can be easily anticipated, the size of the sand bar was closely linked to the nature of incoming waves, and in the case of a rough sea, the foreshore slope was rapidly deformed due to scouring. In mild seas, several sand waves were formed near the shoreline, and when the exposure time was the same, the size of the sand waves was not as large as in rough seas.
{"title":"Development of Physics-Based Morphology Model with an Emphasis on the Interaction of Incoming Waves with Transient Bed Profile due to Scouring and Accretion using Dynamic Mesh","authors":"Y. Cho","doi":"10.20481/kscdp.2021.8.4.211","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.211","url":null,"abstract":"A physics-based morphology model [Seoul Foam] was developed using the dynamic mesh technique to explain the interaction between the sea bed, which undergoes deformation due to siltation and scouring, and the incoming waves. In doing so, OlaFlow, an Open Foam-based toolbox, was used as a hydrodynamic model. To verify the proposed physically-based morphology [Seoul Foam] in this study, numerical simulations of the shoaling process over the beach of the uniform slope were implemented. The numerical result shows that the formation process of a sand bar over the foreshore was successfully simulated. As can be easily anticipated, the size of the sand bar was closely linked to the nature of incoming waves, and in the case of a rough sea, the foreshore slope was rapidly deformed due to scouring. In mild seas, several sand waves were formed near the shoreline, and when the exposure time was the same, the size of the sand waves was not as large as in rough seas.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132942568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-30DOI: 10.20481/kscdp.2021.8.4.275
Young-Taek Kim
In this study, the hydraulic model tests for the single chamber perforated wall caisson were performed to investigate the reflection coefficients according to the slit shapes. The perforated wall with vertical and horizontal slits was applied to the tests. The random waves were used for the test by using Bretschneider-Mitsuyasu frequency spectrum. The similar reflection coefficients were measured in the vertical and horizontal slit caisson within a similar perforation ratio and area. The reflection coefficient according to relative slit length(S/Hs) was analyzed and the minimum reflection coefficients were measured in relatively small S/Hs (=2.7). The results from horizontal slits showed similar trends with those from the vertical slit perforated wall.
{"title":"Model Test about Reflection Coefficient for Perforated Wall Caisson according to Perforated Wall Shapes: Single Chamber Open Slit Caisson","authors":"Young-Taek Kim","doi":"10.20481/kscdp.2021.8.4.275","DOIUrl":"https://doi.org/10.20481/kscdp.2021.8.4.275","url":null,"abstract":"In this study, the hydraulic model tests for the single chamber perforated wall caisson were performed to investigate the reflection coefficients according to the slit shapes. The perforated wall with vertical and horizontal slits was applied to the tests. The random waves were used for the test by using Bretschneider-Mitsuyasu frequency spectrum. The similar reflection coefficients were measured in the vertical and horizontal slit caisson within a similar perforation ratio and area. The reflection coefficient according to relative slit length(S/Hs) was analyzed and the minimum reflection coefficients were measured in relatively small S/Hs (=2.7). The results from horizontal slits showed similar trends with those from the vertical slit perforated wall.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129883461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：