Hydraulic structures such as "Wando" and the associated Turbulent structure

“莞岛”等水工结构及相关的湍流结构

• 批准号: 07555641
• 负责人: NEZU Iehisa
• 金额: $ 0.83万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555641/
• 关键词: Open-channel Flows; Wando; Turbalence; Vegetated Flow; dike works; Laser Doppler anemometer; Coherent vortex; Separated vortex; レーザ流速計; 剥離流れ; 局所流; 非定常性

The purpose of this study is to obtain technological guides to design the artificial shore swamp ("Wando") in order to make a nature abundant river environment. The functions expected to the "Wando" are the stagnation of flow, the deposition of suspended sediment, the maintenance of water quality and the stability against flood. The study subject is to clarify and control the turbulent structure around the spur dikes and to clarify the mixing mechanism between the main flow and the vegetated flow. The nature of flow and turbulent structure around the spur dikes with various permeability were investigated experimentally. The processes of momentum exchange are different from each other with respect to the permeability of the spur dike. When spur dike is non-permeable, a strong circulation is generated behind the spur dike, but it diminishes in the movable-bed condition, because of massive scour and deposition. When the permeability is relatively small, the secondary flow is generated and plays an important role on the mixing process. In the submerged spur dike, the mixing completed in ash ort distance but the lateral difference of the streamwise velocity is not reduced for a long reach. The permeable spur dike with refracted flow has mild effects for resistance and scouring but can make broad circulation zone behind it.Next, the effects of vegetation along riverbank on the flow were investigated. The flow and vortex structures are studied experimentally in compound open channel flows with loosely and densely wooded zone on flood plains. The interaction between the flow in trees and ambient flow generates characteristic 3-D flow structures. The large-scale periodic vortex motion was observed in these vegetated flows and it could be regenerated by using the unsteady depth-averaged 2-D simulation. We believe that the results of this study give useful knowledge for designing artificial "Wando".

本研究旨在为人工海岸沼泽的设计提供技术指导，以创造一个自然丰富的河流环境。“莞岛”的功能是滞流、沉淀悬浮泥沙、保持水质和防洪稳定。本文的研究目的是弄清和控制丁坝周围的紊流结构，弄清丁坝水流与植被水流的掺混机理。通过试验研究了不同透水率丁坝周围的水流特性和紊动结构。丁坝的动量交换过程因丁坝的渗透性而异。丁坝不透水时，丁坝后产生较强的环流，但在动床条件下，由于大量冲淤，环流减弱。当渗透率相对较小时，二次流产生，并在混合过程中起重要作用。在淹没丁坝中，混合在短距离内完成，但在长河段内，流向流速的横向差异并没有减小。折射流透水丁坝的阻力和冲刷作用较弱，但可以在其后面形成较宽的环流区。其次，研究了沿着植被对水流的影响。本文对滩地疏林和密林复合明渠水流的流动和涡结构进行了实验研究。树木中的水流与周围水流的相互作用产生了特征性的三维水流结构。在这些植被流中观察到大尺度的周期性涡运动，并可以通过使用非定常深度平均的二维模拟来再生。我们相信，本研究的结果提供了有用的知识，设计人工“丸道”。

项目成果

Iehisa Nezu: "Turbulent structures in open-channel flows over wavy boundary" Flow Modeling and Turbulence Measurements (eds.C.J.Chen et al.), Balkema. 91-98 (1996)

Iehisa Nezu：“波状边界上明渠流动的湍流结构”流动建模和湍流测量（eds.C.J.Chen 等人），Balkema。

Akihiro Tominaga: "Numerical study on turbulent structure over square and circular strip roughness in open channel flows" Flow Modeling and Turbulence Measurements (eds.C.J.Chen et al.),Balkema. 505-512 (1996)

Akihiro Tominaga：“明渠流中方形和圆形条带粗糙度上的湍流结构的数值研究”流动建模和湍流测量（eds.C.J.Chen 等人），Balkema。

Iehisa Nezu: "Turbulent Structures of Free Shear Layer over Cavity Using Fiber-Optic LDA," Proc. of 26th Congress of IAHR, London,. 1. 397-402 (1995)

Iehisa Nezu：“使用光纤 LDA 的空腔上自由剪切层的湍流结构”，Proc。

Iehisa Nezu: "Measurements of horizontal coherent vortices between main-channel and flood-plains by using particle-tracking velocimetry" Flow Modeling and Turbulence Measurements (eds.C.J.Chen et al.), Balkema. 229-236 (1996)

Iehisa Nezu：“使用粒子跟踪测速法测量主河道和洪泛区之间的水平相干涡流”流动建模和湍流测量（eds.C.J.Chen 等人），Balkema。

Iehisa Nezu: "Experimental and numerical study on 3-D turbulent structures in compound open-channel flows" Flow Modeling and Turbulence Measurements (eds.C.J.Chen et al.),Balkema. 65-74 (1996)

Iehisa Nezu：“复合明渠流中 3-D 湍流结构的实验和数值研究”流动建模和湍流测量（eds.C.J.Chen 等人），Balkema。