An open channel flume with a central 180-degree bend with a rigid bed is designed to obtain a better understanding of the complex flow pattern around a T-shaped spur dike located in a sharp bend. The 3-dimensional velocities are measured by using an acoustic Doppler velocimetry under clear-water conditions. This study’s primary objective is to compare variations of the mean flow pattern along a 180-degree bend with a variety of T-shaped spur dike lengths. In order to do so, parameters such as streamlines, the maximum velocity distribution, and the secondary flow strength under the influence of three T-shaped spur dike lengths will be analyzed and then compared with the case where no spur dikes are implemented. The results show that with the spur dike placed at the bend apex, the mean secondary flow strength at that range increases by approximately 2.5 times. In addition, a 67% increase in the length of the wing and web of the spur dike leads to a 27% growth in the mean secondary flow strength along the bend.

中文翻译：

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T形丁坝长度对沿180度急弯的平均流量特性的影响

设计有一个带有刚性床身的中心弯曲180度的明渠水槽，以更好地了解位于急弯处的T形丁坝周围的复杂流态。在清水条件下，通过使用声学多普勒测速仪测量3维速度。这项研究的主要目的是比较各种T型丁字丁坝长度沿180度弯头的平均流量模式的变化。为此，将分析在三个T形丁坝长度的影响下的流线，最大速度分布和二次流动强度等参数，然后将其与未实施丁坝的情况进行比较。结果表明，将丁坝放置在弯曲顶点处，在该范围内的平均二次流动强度增加了约2.5倍。此外，丁坝的机翼和腹板长度增加67％，导致沿弯道的平均二次流强度增加27％。