| WAVE BOTTOM LAYERS DYNAMIC WITH SUSPENDED SEDIMENT OVER VORTEX RIPPLES |
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| 作者姓名： | JIANGChang-bo BAIYu-chuan ZHAOZi-dan ZHANGHong-wu |
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| 作者单位： | [1]CollegeofRiverandOceanEngineeringChangshaUniversityofScienceandTechnology,Changsha410076,China [2]InstituteofSedimentonRiverandCoastEngineering,TianjinUniversity,Tianjin300072,China [3]SchoolofCivilEngineering,TsinghuaUniversity,Beijing100084,China |
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| 基金项目： | ProjectsupportedbytheNationalNaturalScienceFoundationofChina.(GrantNos:10 2 0 2 0 0 3and 5 0 12 5 92 4 ) |
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| 摘 要： | Vortex ripple is widely formed in the coastal region, and the dynamic of vortex is quite important because it is responsible for sediment transport. The flow structure around the vortex ripples can be modeled as 2D flow due to the geometry of the flow boundaries. In this paper, 2D Large-Ed-dy-Simulation (LES) method was used to predict the flow structure and the dynamic of vortex in the bottom layers under the action of the wave, the numerical simulation results show a completely process of vortex formation, evolvement and disappearance. Based on the study of flow structure, the suspended sediment transport was modeled in present paper. The simulated sediment concentrations were compared to measurements from the literature. The agreement between the time averaged simulated concentration profiles and measurements is satisfactory. For a high setting velocity, the suspended sediment is confined to the vicinity of the bed, and it is dominated by the local bottom shear stress. For a small setting velocity, the suspension is more dominated by the characteristic of vortex. There are two suspended sediment transport peaks observed in the cross-section at the trough and crest in the half period, the second peak is due to the separation bubble taking the sediment.
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| 关 键 词： | 波边界层 涡流波纹 数值模拟 悬浮沉积物 流体力学 |
WAVE BOTTOM LAYERS DYNAMIC WITH SUSPENDED SEDIMENT OVER VORTEX RIPPLES |
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| JIANGChang-bo BAIYu-chuan ZHAOZi-dan ZHANGHong-wu.WAVE BOTTOM LAYERS DYNAMIC WITH SUSPENDED SEDIMENT OVER VORTEX RIPPLES[J].Journal of Hydrodynamics,2004,16(2):201-208. |
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| Authors: | JIANG Chang-bo College of River and Ocean Engineering Changsha University of Science and Technology Changsha China School of Civil Engineering Tsinghua University Beijing China BAI Yu-chuan ZHAO Zi-dan Institute of Sediment on River and Coast Engineering Tianjin University Tianjin China ZHANG Hong-wu School of Civil Engineering Tsinghua University Beijing China |
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| Affiliation: | JIANG Chang-bo College of River and Ocean Engineering Changsha University of Science and Technology,Changsha 410076,China,School of Civil Engineering,Tsinghua University,Beijing 100084,China BAI Yu-chuan,ZHAO Zi-dan Institute of Sediment on River and Coast Engineering,Tianjin University,Tianjin 300072,China ZHANG Hong-wu School of Civil Engineering,Tsinghua University,Beijing 100084,China |
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| Abstract: | Vortex ripple is widely formed in the coastal region, and the dynamic of vortex is quite important because it is responsible for sediment transport. The flow structure around the vortex ripples can be modeled as 2D flow due to the geometry of the flow boundaries. In this paper, 2D Large-Eddy-Simulation (LES) method was used to predict the flow structure and the dynamic of vortex in the bottom layers under the action of the wave, the numerical simulation results show a completely process of vortex formation, evolvement and disappearance. Based on the study of flow structure, the suspended sediment transport was modeled in present paper. The simulated sediment concentrations were compared to measurements from the literature. The agreement between the time averaged simulated concentration profiles and measurements is satisfactory. For a high setting velocity, the suspended sediment is confined to the vicinity of the bed, and it is dominated by the local bottom shear stress. For a small setting velocity, the suspension is more dominated by the characteristic of vortex. There are two suspended sediment transport peaks observed in the cross-section at the trough and crest in the half period, the second peak is due to the separation bubble taking the sediment. |
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| Keywords: | wave boundary layer vortex ripple suspended sediment numerical model |
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