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Papers by Yun-Chih Chiang
2022 6th International Conference on Imaging, Signal Processing and Communications (ICISPC), Jul 1, 2022
This study using UAV equipped with infrared thermal imager to analyze the surface temperature of ... more This study using UAV equipped with infrared thermal imager to analyze the surface temperature of sea area. The close-target calibration method was designed to improve the distance relationship between the infrared thermal image and the surface temperature of the measurement target. The analysis results show that the error at 12:00 is 4.98%, and the error at 10:00 is 0.52%. The experimental results show that when using
the close-target calibration method to measure the surface temperature of sea area, the noon period should be avoided. It is recommended to take aerial shots in the morning or afternoon (14:00).
Journal of Marine Science and Technology
在以往海岸地形變遷模擬案例發現，基於二維平面水深積分平均流場配合總漂砂量公式之海岸地形變遷模式在碎波帶內往往無法準確模擬，主要原因為碎波帶內底床上方存在一水下逆流所致，加上長期地形變遷模擬常於碎... more 在以往海岸地形變遷模擬案例發現，基於二維平面水深積分平均流場配合總漂砂量公式之海岸地形變遷模式在碎波帶內往往無法準確模擬，主要原因為碎波帶內底床上方存在一水下逆流所致，加上長期地形變遷模擬常於碎波帶內發生數值震盪情形，因此實有必要針對上述問題進行整體海岸地形變遷模式改良。體海岸地形變遷模式包括四部分：波浪傳遞模式、水理流場模式、海岸漂砂模式及地形變化模式。在波場模式部分，本文基於解析碎波前後高非線性問題及碎波後再生波回復的解析，以Nwogu(1993)所推導以任意水深形式表示之二維布斯尼斯克方程式為基礎，並加入Kennedy et al. (2000)建議利用水位時變率作為碎波及回復波指標，建立適用於模擬在近岸海域任意變水深地形下之平面波場模式。而流場模式方面，本文主要以前述平面水深積分平均流場模式為基礎，配合1DV 模式架構擬三維(quasi-3D)的流場數值模式，剪應力項以平面二維波流場模式計算結果之波高、碎波波能消散及平均水位分布等呈現，並與前人研究成果進行驗證結果良好，顯示本文發展之擬三維流場模式之正確性及準確性。海岸漂砂量模式方面，為發展可分析水深方向不均特性的漂砂量公式方面，本文將總漂砂量分為懸浮載與底床載，分析過程中並引入波浪近岸傳遞的不對稱性及沙漣存在的影響，並藉由非線性波理論將相關待定係數公式化增加應用範圍，最後並與前人實驗結果及知名漂砂公式進行驗證。而地形變化模式改良部分，本文首先探討數值震盪原因後，發展每一時階漂砂量隨底床坡度修正之二步驟三時階WENO海岸地形變遷數值模式，精度可達O( )。模式建立後針對實際現場複雜海岸進行驗證結果良好。體模式建置完成後，利用DHI之LIP11D動床沙洲遷移實驗結果進行驗證，並應用於符合暴風型海灘條件等坡度理想平直海岸沙洲生成模擬，顯示本文發展模式之可行性與實用性。最後並以和美漁港防波堤減量實例計算碎波帶內港口附近侵淤情形並與實際監測結果比較結果良好，顯示本文所發展模式在實際海岸地形預測具高精確度及可信賴度，未來可供國內海岸保護規劃、港灣工程及大型海岸開發海岸地形變遷評估分析之用。Coastal morphological models are indispensable and powerful tools that allow harbor and hydraulic engineers to pre...
In order to increase the overall bearing capacity of a wind turbine foundation, a composite type ... more In order to increase the overall bearing capacity of a wind turbine foundation, a composite type of suction pile is proposed in this paper. Numerical analysis of a suction pile with enlarged lid size subjected to combined lateral and axial loading is presented in the paper. Analysis results prove a suction pile with enlarged lid size has better performance on both the overall bearing capacity and the stability of the foundation.
The characteristics of sediment transport occurring in the nearshore region are mainly produced b... more The characteristics of sediment transport occurring in the nearshore region are mainly produced by the interaction of the coastal morphological evolution and nearshore hydrodynamics from waves, wave-driven-currents and tidal currents. In this study, we discussed how various seasonal marine conditions can influence the characteristics of sediment transport in spatial and temporal with filed observations near the estuary of Cho-Shui River. The spatial distribution of grain size is decreasing alongshore from the estuary during summer, and is decreasing offshore from shoreline but no significant changing alongshore during winter. Comparing with the numerical simulation with DHI MIKE-21, it shows that sands banked up at estuary caused by an excess of river sediments transport with smaller grain size in summer, and that estuarine erosion results from the interplay of less river sediment transport supplied and hydrodynamic forcing scoured with larger grain size by waves in winter. In this paper, the different characteristic associated from seasonal marine conditions, river sediment transports, and estuarine morphologies have been discussed, and the influence of typhoon also analyzed.
Breakwater structure deterioration or damages can jeopardize dike safety and function. To manage ... more Breakwater structure deterioration or damages can jeopardize dike safety and function. To manage breakwater maintenance and enhance work efficiency, we integrated cloud computing into a breakwater inspection system. The purpose was to facilitate the efficient management of breakwater maintenance. The operating framework for inspection and maintenance in this study was developed by referring to assessment methods used in “Study of the Standard Codes of Maintenance and Management for Harbor Structures.” The breakwater structures located in Bisha Harbor of Badouzi Fishing Port were used as a case study. The field inspection results were analyzed to evaluate the suitability of the grading intervals of the condition indices for the breakwater structures. Subsequently, a breakwater inspection and maintenance system was developed. The Android operating system was employed to develop breakwater inspection application software that can be executed on the Google Web Toolkit platform. This app...
Prediction of the dynamic behavior of onshore and offshore sandbar systems could be of great impo... more Prediction of the dynamic behavior of onshore and offshore sandbar systems could be of great importance. A quasi-three-dimensional (Q3D) morphological numerical model for sandbar forming and migrating shoreward has been developed. The model combines a Boussinesq wave model, a two-dimensional depth integrated wave-driven currents model with a one-dimensional vertical currents model for maximum undertow and onshore acceleration skewness of wave orbital velocities near sandbar crest. The combined model makes a simultaneous simulation of the sandbar-forming and shoreward moving processes associated with the onshore acceleration skewness of wave orbital velocities and the horizontal wave-driven circulation currents. The numerical results of sandbar formation are verified by the DHI LIP11D test1b with good agreement in wave heights, vertical velocities, and sandbar migration. Therefore, the present model is suitable for prediction of sandbar formations and migrations. The sandbar forming ...
Numerical modeling of coastal morphodynamic evolution is a powerful tool for the planning and des... more Numerical modeling of coastal morphodynamic evolution is a powerful tool for the planning and design of coastal engineering. The coastal morphological modeling system is based on the sediment conservation law, which couples modules for waves, wave-driven currents, and sediment transport rates. The numerical scheme for the sediment conservation law and nonlinear coupling between these modules can lead to dispersions, diffusions, spurious oscillations and stability problems that are still not well developed. In this paper, the bedslope updating techniques, oscillation removal schemes, and 2-step, 3-time-level temporal discretization are employed to avoid oscillations and improve the stability of the coastal morphological model with accuracy up to 255 (, , ) Ot x y ∆∆ ∆ . Finally, the model shows good performance for coastal areas with complex topography.
Water, 2021
In this study, a hydrodynamic model was used that includes the effects of wave–current interactio... more In this study, a hydrodynamic model was used that includes the effects of wave–current interactions to simulate the wave and current patterns before and after offshore wind turbine installation in western Taiwan. By simulating the waves and currents after the offshore wind turbine was established, the waves and currents caused by the wind turbine were seen to have a limited range of influence, which is probably within an area about four to five times the size of the diameter (12–15 m) of the foundation structure. Overall, the analysis of the simulation results of the wave and current patterns after the offshore wind turbines were established shows that the underwater foundation only affected the local area near the pile structure. The wind farm (code E) of the research case can be equipped with about 720 cage cultures; if this is extended to other wind farms in the western sea area, it should be possible to produce economic-scale farming operations such as offshore wind power and fi...
International Journal of Offshore and Polar Engineering, 2011
Reflection characteristics of solid boundaries are important parameters when using numerical simu... more Reflection characteristics of solid boundaries are important parameters when using numerical simulation to study harbor tranquility. Incorrect treatments of the reflection characteristics can result in an erroneous amplification curve for the harbor. This study investigates harbor reflection experimentally and numerically. In particular, we study frequency-dependent reflection characteristics of the quay-wall in a harbor by performing a series of laboratory experiments using porous quaywalls with various porosities and wall thicknesses. Experimental results of the frequency-dependent wave reflection coefficients are then introduced into numerical models of harbor tranquility to treat the boundary reflecting problem. Simulation results show that the reflection coefficient significantly influenced the wave amplification curve and resonant wave period. Also, the energy dissipation efficiency of the quay-wall on waves seems to be overestimated when the quay-wall’s reflection coefficient...
IOP Conference Series: Earth and Environmental Science, Jul 1, 2018
Yanliao Beach, part of Taiwan's Northeast Coast National Scenic Area, is a major sightseeing ... more Yanliao Beach, part of Taiwan's Northeast Coast National Scenic Area, is a major sightseeing and recreation spot. In recent years, the number of tourists has increased, and maintaining the beach's recreation function has become crucial. In 2007, Typhoon Krosa caused substantial beach erosion at Yanliao Beach; sand dunes collapsed, resulting in a beach scarp and endangering facilities toward the back of the beach. To protect the sand dunes and beach scarp of the post-typhoon topography, based on long-term Yanliao Beach topographic survey information and long-term tidal water level records, this study conducted an integrated artificial beach nourishment method that comprised replenishing the coastal beach and dunes. The planned areas for sand replenishment were those above the mean high water line. This beach nourishment measure protected the dunes from collapsing further and mitigated the risk of beach nourishment polluting the water in front of the beach. Topographic survey results revealed that the large amount of sand deposited in the intertidal zone resulted in the 0 m shoreline advancing toward the seaside. The width of the beach increased, indicating the success of this integrated beach nourishment method.
Polymer Chemistry
We report the synthesis, morphology, and properties of intrinsically stretchable isoindigo-bithio... more We report the synthesis, morphology, and properties of intrinsically stretchable isoindigo-bithiophene conjugated copolymers (PII2T) by incorporating octyldecane (OD) and polyacrylate amide (PAAm) side chain. Stronger molecular aggregation and crystallinity could...
Accurate prediction of sediment transport rates is an important element in morphological studies ... more Accurate prediction of sediment transport rates is an important element in morphological studies for the coastal environment. The purpose of this paper is to develop a quasi-three-dimensional (Q-3D) total load sediment transport formula based on the bed load and suspended load transport driven by waves and wave induced nearshore currents for the coastal area. The model consists of a two-dimensional nonlinear wave model, a two-dimensional depth integrated model for wave-driven currents with a model for undertow circulation currents and a coastal sediment transport formula with bed load and suspended load. The bed load sediment transport rate are calculated by the flow velocity coupled with wave and wave driven current near bed, and the suspended load is integrated the sediment concentration calculated by coupled velocity in vertical direction. A comparison has been carried out between the computed sediment transport rates with experimental results. The numerical results obtained are ...
Water
The objective of this study was to adequately examine potential wave fields, flow fields, and sus... more The objective of this study was to adequately examine potential wave fields, flow fields, and suspended load changes in different wind turbine foundations. Accordingly, this study applied the hydrodynamic model to simulate waves, currents, and suspended load in the study area. The simulation results are based on the assumption that dredging and rubble bed trimming were performed for 8 h and that the per foundation setting operation was completed in 2 h. The influence on the tripile and jacket was larger than that on the monopile, and the influence time was longer. However, due to the influence of tidal currents on the sea, the suspended load also became more acceptable than the initial concentration. From a macroscopic perspective, the different foundations did not sufficiently affect the study area. From a microscopic perspective, changes in the suspended load were only limited to areas surrounding the piles after the installation of the wind turbines.
2022 6th International Conference on Imaging, Signal Processing and Communications (ICISPC), Jul 1, 2022
This study using UAV equipped with infrared thermal imager to analyze the surface temperature of ... more This study using UAV equipped with infrared thermal imager to analyze the surface temperature of sea area. The close-target calibration method was designed to improve the distance relationship between the infrared thermal image and the surface temperature of the measurement target. The analysis results show that the error at 12:00 is 4.98%, and the error at 10:00 is 0.52%. The experimental results show that when using
the close-target calibration method to measure the surface temperature of sea area, the noon period should be avoided. It is recommended to take aerial shots in the morning or afternoon (14:00).
Journal of Marine Science and Technology
在以往海岸地形變遷模擬案例發現，基於二維平面水深積分平均流場配合總漂砂量公式之海岸地形變遷模式在碎波帶內往往無法準確模擬，主要原因為碎波帶內底床上方存在一水下逆流所致，加上長期地形變遷模擬常於碎... more 在以往海岸地形變遷模擬案例發現，基於二維平面水深積分平均流場配合總漂砂量公式之海岸地形變遷模式在碎波帶內往往無法準確模擬，主要原因為碎波帶內底床上方存在一水下逆流所致，加上長期地形變遷模擬常於碎波帶內發生數值震盪情形，因此實有必要針對上述問題進行整體海岸地形變遷模式改良。體海岸地形變遷模式包括四部分：波浪傳遞模式、水理流場模式、海岸漂砂模式及地形變化模式。在波場模式部分，本文基於解析碎波前後高非線性問題及碎波後再生波回復的解析，以Nwogu(1993)所推導以任意水深形式表示之二維布斯尼斯克方程式為基礎，並加入Kennedy et al. (2000)建議利用水位時變率作為碎波及回復波指標，建立適用於模擬在近岸海域任意變水深地形下之平面波場模式。而流場模式方面，本文主要以前述平面水深積分平均流場模式為基礎，配合1DV 模式架構擬三維(quasi-3D)的流場數值模式，剪應力項以平面二維波流場模式計算結果之波高、碎波波能消散及平均水位分布等呈現，並與前人研究成果進行驗證結果良好，顯示本文發展之擬三維流場模式之正確性及準確性。海岸漂砂量模式方面，為發展可分析水深方向不均特性的漂砂量公式方面，本文將總漂砂量分為懸浮載與底床載，分析過程中並引入波浪近岸傳遞的不對稱性及沙漣存在的影響，並藉由非線性波理論將相關待定係數公式化增加應用範圍，最後並與前人實驗結果及知名漂砂公式進行驗證。而地形變化模式改良部分，本文首先探討數值震盪原因後，發展每一時階漂砂量隨底床坡度修正之二步驟三時階WENO海岸地形變遷數值模式，精度可達O( )。模式建立後針對實際現場複雜海岸進行驗證結果良好。體模式建置完成後，利用DHI之LIP11D動床沙洲遷移實驗結果進行驗證，並應用於符合暴風型海灘條件等坡度理想平直海岸沙洲生成模擬，顯示本文發展模式之可行性與實用性。最後並以和美漁港防波堤減量實例計算碎波帶內港口附近侵淤情形並與實際監測結果比較結果良好，顯示本文所發展模式在實際海岸地形預測具高精確度及可信賴度，未來可供國內海岸保護規劃、港灣工程及大型海岸開發海岸地形變遷評估分析之用。Coastal morphological models are indispensable and powerful tools that allow harbor and hydraulic engineers to pre...
In order to increase the overall bearing capacity of a wind turbine foundation, a composite type ... more In order to increase the overall bearing capacity of a wind turbine foundation, a composite type of suction pile is proposed in this paper. Numerical analysis of a suction pile with enlarged lid size subjected to combined lateral and axial loading is presented in the paper. Analysis results prove a suction pile with enlarged lid size has better performance on both the overall bearing capacity and the stability of the foundation.
The characteristics of sediment transport occurring in the nearshore region are mainly produced b... more The characteristics of sediment transport occurring in the nearshore region are mainly produced by the interaction of the coastal morphological evolution and nearshore hydrodynamics from waves, wave-driven-currents and tidal currents. In this study, we discussed how various seasonal marine conditions can influence the characteristics of sediment transport in spatial and temporal with filed observations near the estuary of Cho-Shui River. The spatial distribution of grain size is decreasing alongshore from the estuary during summer, and is decreasing offshore from shoreline but no significant changing alongshore during winter. Comparing with the numerical simulation with DHI MIKE-21, it shows that sands banked up at estuary caused by an excess of river sediments transport with smaller grain size in summer, and that estuarine erosion results from the interplay of less river sediment transport supplied and hydrodynamic forcing scoured with larger grain size by waves in winter. In this paper, the different characteristic associated from seasonal marine conditions, river sediment transports, and estuarine morphologies have been discussed, and the influence of typhoon also analyzed.
Breakwater structure deterioration or damages can jeopardize dike safety and function. To manage ... more Breakwater structure deterioration or damages can jeopardize dike safety and function. To manage breakwater maintenance and enhance work efficiency, we integrated cloud computing into a breakwater inspection system. The purpose was to facilitate the efficient management of breakwater maintenance. The operating framework for inspection and maintenance in this study was developed by referring to assessment methods used in “Study of the Standard Codes of Maintenance and Management for Harbor Structures.” The breakwater structures located in Bisha Harbor of Badouzi Fishing Port were used as a case study. The field inspection results were analyzed to evaluate the suitability of the grading intervals of the condition indices for the breakwater structures. Subsequently, a breakwater inspection and maintenance system was developed. The Android operating system was employed to develop breakwater inspection application software that can be executed on the Google Web Toolkit platform. This app...
Prediction of the dynamic behavior of onshore and offshore sandbar systems could be of great impo... more Prediction of the dynamic behavior of onshore and offshore sandbar systems could be of great importance. A quasi-three-dimensional (Q3D) morphological numerical model for sandbar forming and migrating shoreward has been developed. The model combines a Boussinesq wave model, a two-dimensional depth integrated wave-driven currents model with a one-dimensional vertical currents model for maximum undertow and onshore acceleration skewness of wave orbital velocities near sandbar crest. The combined model makes a simultaneous simulation of the sandbar-forming and shoreward moving processes associated with the onshore acceleration skewness of wave orbital velocities and the horizontal wave-driven circulation currents. The numerical results of sandbar formation are verified by the DHI LIP11D test1b with good agreement in wave heights, vertical velocities, and sandbar migration. Therefore, the present model is suitable for prediction of sandbar formations and migrations. The sandbar forming ...
Numerical modeling of coastal morphodynamic evolution is a powerful tool for the planning and des... more Numerical modeling of coastal morphodynamic evolution is a powerful tool for the planning and design of coastal engineering. The coastal morphological modeling system is based on the sediment conservation law, which couples modules for waves, wave-driven currents, and sediment transport rates. The numerical scheme for the sediment conservation law and nonlinear coupling between these modules can lead to dispersions, diffusions, spurious oscillations and stability problems that are still not well developed. In this paper, the bedslope updating techniques, oscillation removal schemes, and 2-step, 3-time-level temporal discretization are employed to avoid oscillations and improve the stability of the coastal morphological model with accuracy up to 255 (, , ) Ot x y ∆∆ ∆ . Finally, the model shows good performance for coastal areas with complex topography.
Water, 2021
In this study, a hydrodynamic model was used that includes the effects of wave–current interactio... more In this study, a hydrodynamic model was used that includes the effects of wave–current interactions to simulate the wave and current patterns before and after offshore wind turbine installation in western Taiwan. By simulating the waves and currents after the offshore wind turbine was established, the waves and currents caused by the wind turbine were seen to have a limited range of influence, which is probably within an area about four to five times the size of the diameter (12–15 m) of the foundation structure. Overall, the analysis of the simulation results of the wave and current patterns after the offshore wind turbines were established shows that the underwater foundation only affected the local area near the pile structure. The wind farm (code E) of the research case can be equipped with about 720 cage cultures; if this is extended to other wind farms in the western sea area, it should be possible to produce economic-scale farming operations such as offshore wind power and fi...
International Journal of Offshore and Polar Engineering, 2011
Reflection characteristics of solid boundaries are important parameters when using numerical simu... more Reflection characteristics of solid boundaries are important parameters when using numerical simulation to study harbor tranquility. Incorrect treatments of the reflection characteristics can result in an erroneous amplification curve for the harbor. This study investigates harbor reflection experimentally and numerically. In particular, we study frequency-dependent reflection characteristics of the quay-wall in a harbor by performing a series of laboratory experiments using porous quaywalls with various porosities and wall thicknesses. Experimental results of the frequency-dependent wave reflection coefficients are then introduced into numerical models of harbor tranquility to treat the boundary reflecting problem. Simulation results show that the reflection coefficient significantly influenced the wave amplification curve and resonant wave period. Also, the energy dissipation efficiency of the quay-wall on waves seems to be overestimated when the quay-wall’s reflection coefficient...
IOP Conference Series: Earth and Environmental Science, Jul 1, 2018
Yanliao Beach, part of Taiwan's Northeast Coast National Scenic Area, is a major sightseeing ... more Yanliao Beach, part of Taiwan's Northeast Coast National Scenic Area, is a major sightseeing and recreation spot. In recent years, the number of tourists has increased, and maintaining the beach's recreation function has become crucial. In 2007, Typhoon Krosa caused substantial beach erosion at Yanliao Beach; sand dunes collapsed, resulting in a beach scarp and endangering facilities toward the back of the beach. To protect the sand dunes and beach scarp of the post-typhoon topography, based on long-term Yanliao Beach topographic survey information and long-term tidal water level records, this study conducted an integrated artificial beach nourishment method that comprised replenishing the coastal beach and dunes. The planned areas for sand replenishment were those above the mean high water line. This beach nourishment measure protected the dunes from collapsing further and mitigated the risk of beach nourishment polluting the water in front of the beach. Topographic survey results revealed that the large amount of sand deposited in the intertidal zone resulted in the 0 m shoreline advancing toward the seaside. The width of the beach increased, indicating the success of this integrated beach nourishment method.
Polymer Chemistry
We report the synthesis, morphology, and properties of intrinsically stretchable isoindigo-bithio... more We report the synthesis, morphology, and properties of intrinsically stretchable isoindigo-bithiophene conjugated copolymers (PII2T) by incorporating octyldecane (OD) and polyacrylate amide (PAAm) side chain. Stronger molecular aggregation and crystallinity could...
Accurate prediction of sediment transport rates is an important element in morphological studies ... more Accurate prediction of sediment transport rates is an important element in morphological studies for the coastal environment. The purpose of this paper is to develop a quasi-three-dimensional (Q-3D) total load sediment transport formula based on the bed load and suspended load transport driven by waves and wave induced nearshore currents for the coastal area. The model consists of a two-dimensional nonlinear wave model, a two-dimensional depth integrated model for wave-driven currents with a model for undertow circulation currents and a coastal sediment transport formula with bed load and suspended load. The bed load sediment transport rate are calculated by the flow velocity coupled with wave and wave driven current near bed, and the suspended load is integrated the sediment concentration calculated by coupled velocity in vertical direction. A comparison has been carried out between the computed sediment transport rates with experimental results. The numerical results obtained are ...
Water
The objective of this study was to adequately examine potential wave fields, flow fields, and sus... more The objective of this study was to adequately examine potential wave fields, flow fields, and suspended load changes in different wind turbine foundations. Accordingly, this study applied the hydrodynamic model to simulate waves, currents, and suspended load in the study area. The simulation results are based on the assumption that dredging and rubble bed trimming were performed for 8 h and that the per foundation setting operation was completed in 2 h. The influence on the tripile and jacket was larger than that on the monopile, and the influence time was longer. However, due to the influence of tidal currents on the sea, the suspended load also became more acceptable than the initial concentration. From a macroscopic perspective, the different foundations did not sufficiently affect the study area. From a microscopic perspective, changes in the suspended load were only limited to areas surrounding the piles after the installation of the wind turbines.