The bar–pool morphology is a typical feature of meandering channels that strongly affects flow and transport patterns. In this study, the three-dimensional flow velocity was measured in detail at six cross-sections in two continuous reverse bends with pool–point bar topography. The streamwise velocity, cross-sectional distributions of circulation, net transversal flow, turbulent kinetic energy (TKE) and turbulent shear stress (TSS) were analysed. High values of the streamwise velocity, TKE and TSS were located in the point bar region (PBR), which were closer to the bed surface in the downstream bend. The circulations, including the main circulation (MC), upper remaining circulation (URC) and outer-bank circulation (OBC), were observed to interact with each other and affect the net transversal flow. The URC was found to exist in the PBR of the downstream bend, which restrained the tendency of the MC to move towards the inner bank. The OBC decreased the net transversal flux of fluid mass towards the inner bank or increased the flux towards the outer bank. The variations in the flow characteristics for different water depths were also analysed. The experimental data can help to validate numerical simulations and predict the evolution of meandering channels, which will provide a technical basis for river regulation.

中文翻译：

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具有池点坝形地形的连续弯管中的流动特性

坝池形态是曲折通道的典型特征，它强烈影响流动和运输模式。在这项研究中，详细测量了两个连续反向弯道的六个横截面的三维流速，该弯道具有池点杆地形。分析了流向速度、环流横截面分布、净横向流动、湍动能（TKE）和湍流剪应力（TSS）。流向速度、TKE 和 TSS 的高值位于点坝区域 (PBR)，该区域更靠近下游弯道的床表面。观察到包括主环流（MC）、上部剩余环流（URC）和外岸环流（OBC）在内的环流相互影响并影响净横向流量。发现 URC 存在于下游弯道的 PBR 中，这抑制了 MC 向内岸移动的趋势。OBC 减少了流向内岸的流体质量的净横向通量或增加了流向外岸的通量。还分析了不同水深下流动特性的变化。实验数据有助于验证数值模拟和预测曲流河道的演变，为河流整治提供技术依据。