The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Jan Joost Schouten - One of the best experts on this subject based on the ideXlab platform.
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Edge scour at scour protections around piles in the marine environment - Laboratory and Field Investigation
Coastal Engineering, 2015Co-Authors: Thor Ugelvig Petersen, B. Mutlu Sumer, Jørgen Fredsøe, Tim Raaijmakers, Jan Joost SchoutenAbstract:Abstract When building offshore wind turbines with monopile foundations, scour protection typically is placed to avoid scouring of the soil close to the monopile. An important aspect is that the scour protection itself causes erosion, inflicted by the local increase in current and/or wave velocities and in turn increased bed shear stresses. Scour of the edge material alongside the scour protection may cause deformations and failure of the scour protection of offshore wind turbine foundations. This can reduce the stability of the stone layer and cause exposure of cables running between the monopiles where they go from buried to the transition piece on the foundation. Although much information is available on the design of scour protection systems around monopiles, little is known on the mechanisms causing edge scour and the equilibrium stages of the edge scour process in steady current, waves and combined waves and current. This paper presents an extensive experimental campaign to explain the edge scour process in current and combined irregular waves and current, as well as tidal current. The three-dimensional flow Field around the pile and scour protection is resolved by particle image velocimetry and bed shear stress measurements, showing a local increase in the flow velocities and bed shear stresses leading to increased sediment transport and scour. The governing process in steady current is a pair of symmetrical counter-rotating vortices emerging in the near bed region in the wake of the pile and scour protection, causing a significant downstream scour hole. It is found that the equilibrium scour hole depth and length scales with the pile diameter and the ratio between the thickness- and the width of the scour protection. In the second part of the present paper, the results from the experimental campaign are compared with the edge scour experienced in practice, outlined by a survey program of the offshore wind park Egmond Aan Zee and a published Field Investigation of Scroby Sands OWF by Whitehouse et al. (2011).
Guangcheng Shao - One of the best experts on this subject based on the ideXlab platform.
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soil erosion characteristics of ditch banks during reclamation of a saline sodic soil in a coastal region of china Field Investigation and rainfall simulation
Catena, 2014Co-Authors: Dongli She, Yuanhang Fei, Zhipeng Liu, Dongdong Liu, Guangcheng ShaoAbstract:Abstract Understanding soil erosion processes is essential for assessing the extent and causes of soil erosion and for planning soil conservation including those on the banks of excavated ditches. Based on a Field Investigation and laboratory rainfall simulation experiments, the soil erosion characteristics of a saline/sodic soil undergoing reclamation that was exposed on irrigation/drainage ditch banks in a coastal region of China were investigated. Preliminary analyses of the data indicated that the soil erosion was more severe from the ditch banks in the coastal region than from those in other areas of China. The annual erosion loss from ditch banks in the most recently reclaimed farmland (2007) was 140 kg/m2, but the erosion modulus decreased significantly (p
Thor Ugelvig Petersen - One of the best experts on this subject based on the ideXlab platform.
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Edge scour at scour protections around piles in the marine environment - Laboratory and Field Investigation
Coastal Engineering, 2015Co-Authors: Thor Ugelvig Petersen, B. Mutlu Sumer, Jørgen Fredsøe, Tim Raaijmakers, Jan Joost SchoutenAbstract:Abstract When building offshore wind turbines with monopile foundations, scour protection typically is placed to avoid scouring of the soil close to the monopile. An important aspect is that the scour protection itself causes erosion, inflicted by the local increase in current and/or wave velocities and in turn increased bed shear stresses. Scour of the edge material alongside the scour protection may cause deformations and failure of the scour protection of offshore wind turbine foundations. This can reduce the stability of the stone layer and cause exposure of cables running between the monopiles where they go from buried to the transition piece on the foundation. Although much information is available on the design of scour protection systems around monopiles, little is known on the mechanisms causing edge scour and the equilibrium stages of the edge scour process in steady current, waves and combined waves and current. This paper presents an extensive experimental campaign to explain the edge scour process in current and combined irregular waves and current, as well as tidal current. The three-dimensional flow Field around the pile and scour protection is resolved by particle image velocimetry and bed shear stress measurements, showing a local increase in the flow velocities and bed shear stresses leading to increased sediment transport and scour. The governing process in steady current is a pair of symmetrical counter-rotating vortices emerging in the near bed region in the wake of the pile and scour protection, causing a significant downstream scour hole. It is found that the equilibrium scour hole depth and length scales with the pile diameter and the ratio between the thickness- and the width of the scour protection. In the second part of the present paper, the results from the experimental campaign are compared with the edge scour experienced in practice, outlined by a survey program of the offshore wind park Egmond Aan Zee and a published Field Investigation of Scroby Sands OWF by Whitehouse et al. (2011).
Dongli She - One of the best experts on this subject based on the ideXlab platform.
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soil erosion characteristics of ditch banks during reclamation of a saline sodic soil in a coastal region of china Field Investigation and rainfall simulation
Catena, 2014Co-Authors: Dongli She, Yuanhang Fei, Zhipeng Liu, Dongdong Liu, Guangcheng ShaoAbstract:Abstract Understanding soil erosion processes is essential for assessing the extent and causes of soil erosion and for planning soil conservation including those on the banks of excavated ditches. Based on a Field Investigation and laboratory rainfall simulation experiments, the soil erosion characteristics of a saline/sodic soil undergoing reclamation that was exposed on irrigation/drainage ditch banks in a coastal region of China were investigated. Preliminary analyses of the data indicated that the soil erosion was more severe from the ditch banks in the coastal region than from those in other areas of China. The annual erosion loss from ditch banks in the most recently reclaimed farmland (2007) was 140 kg/m2, but the erosion modulus decreased significantly (p
Jørgen Fredsøe - One of the best experts on this subject based on the ideXlab platform.
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Edge scour at scour protections around piles in the marine environment - Laboratory and Field Investigation
Coastal Engineering, 2015Co-Authors: Thor Ugelvig Petersen, B. Mutlu Sumer, Jørgen Fredsøe, Tim Raaijmakers, Jan Joost SchoutenAbstract:Abstract When building offshore wind turbines with monopile foundations, scour protection typically is placed to avoid scouring of the soil close to the monopile. An important aspect is that the scour protection itself causes erosion, inflicted by the local increase in current and/or wave velocities and in turn increased bed shear stresses. Scour of the edge material alongside the scour protection may cause deformations and failure of the scour protection of offshore wind turbine foundations. This can reduce the stability of the stone layer and cause exposure of cables running between the monopiles where they go from buried to the transition piece on the foundation. Although much information is available on the design of scour protection systems around monopiles, little is known on the mechanisms causing edge scour and the equilibrium stages of the edge scour process in steady current, waves and combined waves and current. This paper presents an extensive experimental campaign to explain the edge scour process in current and combined irregular waves and current, as well as tidal current. The three-dimensional flow Field around the pile and scour protection is resolved by particle image velocimetry and bed shear stress measurements, showing a local increase in the flow velocities and bed shear stresses leading to increased sediment transport and scour. The governing process in steady current is a pair of symmetrical counter-rotating vortices emerging in the near bed region in the wake of the pile and scour protection, causing a significant downstream scour hole. It is found that the equilibrium scour hole depth and length scales with the pile diameter and the ratio between the thickness- and the width of the scour protection. In the second part of the present paper, the results from the experimental campaign are compared with the edge scour experienced in practice, outlined by a survey program of the offshore wind park Egmond Aan Zee and a published Field Investigation of Scroby Sands OWF by Whitehouse et al. (2011).
