On the Impacts of Ice Cover on Flow Profiles in a Bend
On the Impacts of Ice Cover on Flow Profiles in a Bend
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DOI：
10.1029/2021wr031742
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发表时间：
2022-02
影响因子：
5.4
通讯作者：
T. Le;Berkay Koyuncu
中科院分区：
文献类型：
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作者：
T. Le;Berkay Koyuncu
我们研究了冰覆盖对河流弯曲处的水流和河床剪应力分布的影响。我们使用声学多普勒电流剖面仪在美国北达科他州红河河湾进行现场测量。 2020年和2021年在开放地表和冰覆盖条件下进行了野外活动。我们的结果表明，在完全冰覆盖的情况下，时间平均速度剖面密切遵循四次解（Guo et al., 2017）。虽然开放地表条件下的流动剖面密切遵循床附近的对数定律，但在冰覆盖条件下识别我们的测量数据中的对数层是一项挑战。我们的结果还表明，冰的影响覆盖范围在两岸最为显着，由于湍流与冰盖的相互作用，垂直速度剖面发生了显着的变化。我们的研究结果表明，弯曲曲率和冰覆盖范围都对速度剖面以及河床剪应力的分布有显着影响，我们的研究结果为冰覆盖河流的沉积物输送过程提供了新的见解，特别是在地表覆盖范围快速变化的时期。
We investigate the impact of ice coverage on flow and bed shear stress profiles in a river bend. We perform field measurements using Acoustic Doppler Current Profiler in a bend of the Red River, North Dakota, the United States. Field campaigns were carried out under both open‐surface and ice‐covered conditions in 2020 and 2021. Our results show that the time‐averaged velocity profile follows closely the quartic solution (Guo et al., 2017, under full ice coverage. While the flow profile under open‐surface condition follows closely the logarithmic law near the bed, it is challenging to identify the logarithmic layers in our measured data under ice‐covered condition. Our results also show that the impact of ice coverage is most significant near both banks where the vertical velocity profile is modified significantly due to the interaction of turbulent flows with the ice cover. Our results suggest that the bend curvature and ice coverage both have significant impacts on the velocity profile as well as the distribution of the bed shear stresses. Our findings provide new insights on sediment transport processes of ice‐covered rivers, especially during the break‐up period when the surface coverage changes rapidly.