The presence of a small seepage velocity in streams and rivers induces transfer of mass and momentum near the sediment boundary, causing bank failure and instability of hydraulic structures. This experimental study is intended to report near-bed hydrodynamics and morphological characteristics under the impact of downward seepage. A laboratory investigation was conducted in a sinuous rectangular alluvial channel with rigid sides and movable uniform sand bed. From the distribution of Reynolds shear stress (RSS), the transverse or radial motion of the sediment across the bend was identified. High values of RSS in the outer region relate to higher momentum flux, eroding the outer bend. The contribution probability of ejection and sweep events are highest in the bend region. For seepage, the contribution probability of the events has increased. Moreover, the altered flow with seepage affected the transport of sediment and caused noticeable modifications along the channel bed. With seepage, the erosion rate has been enhanced along the outer bend of the channel.

中文翻译：

---

下渗弯通道近床流动湍流实验研究

溪流和河流中存在的小渗流速度会导致沉积物边界附近的质量和动量转移，从而导致堤岸破坏和水工结构的不稳定。本实验研究旨在报告向下渗流影响下的近床流体动力学和形态特征。实验室调查是在一个弯曲的矩形冲积河道中进行的，该河道具有刚性边和可移动的均匀沙床。根据雷诺剪应力 (RSS) 的分布，确定了沉积物穿过弯曲处的横向或径向运动。外部区域的高 RSS 值与更高的动量通量有关，侵蚀了外部弯曲。弹射和扫掠事件的贡献概率在弯曲区域最高。对于渗流，事件的贡献概率增加了。此外，随着渗流改变的流动影响了沉积物的运输，并导致沿河床发生明显的变化。随着渗流，沿河道外弯的冲蚀率得到提高。