Investigating wave shape effect on sediment transport over migrating ripples using an eulerian two-phase model
Investigating wave shape effect on sediment transport over migrating ripples using an eulerian two-phase model
复制标题
使用欧拉两相模型研究波形对迁移波纹上沉积物输运的影响
DOI：
10.1016/j.coastaleng.2024.104470
复制
发表时间：
2024
影响因子：
4.4
通讯作者：
Chauchat, Julien
中科院分区：
文献类型：
--
作者：
Salimi-Tarazouj, Ali;Hsu, Tian-Jian;Traykovski, Peter;Chauchat, Julien
在给定泥沙粒径、流动周期和流度数的条件下，采用雷诺数平均两相欧拉模型SedFoam，研究了非对称流和偏流对粗砂迁移波纹上泥沙输移的影响。首先，通过加速型偏斜（非对称）振荡流驱动轨道波纹的全尺寸水洞实验对模型进行了验证，在流速、净输沙量和波纹迁移率方面具有较好的一致性。模型结果表明，不对称流动导致悬质和近质泥沙（传统的床质和部分近质泥沙，负责波纹迁移）的净陆上输沙。悬移荷载输运是由“正相位滞后”效应驱动的，而近层输运则是由压力侧边界层的大量侵蚀、背风侧的泥沙雪崩以及压力涡诱导的回流通量驱动的。综上所述，这些过程产生了陆上运输的净费率。相反，对于高能量速度偏斜流，净输运率是离岸导向的。这是由于与陆上近层负载传输速率相比，海上定向悬浮负载传输速率更大，这是由“负相位滞后”效应造成的。与非对称流动相比，由于在陆上流动半循环期间产生更强的背风涡，与背风侧回流相关的较大海上定向通量限制了陆上近层负荷的输送（和迁移）速率。在非对称-偏斜联合流动情况下，近层负荷和运移速率均高于非对称流动情况。此外，由于负相位滞后效应（由于速度偏度）和正相位滞后效应（由于加速度偏度）之间的竞争，与偏斜流情况相比，海上导向悬浮载荷要小得多。因此，净输运速率为陆上导向，但略小于非对称流动情况。
A Reynolds-averaged two-phase Eulerian model for sediment transport, SedFoam, is utilized in a two-dimensional domain for a given sediment grain size, flow period, and mobility number to study the asymmetric and skewed flow effects on the sediment transport over coarse-sand migrating ripples. First, the model is validated with a full-scale water tunnel experiment of orbital ripple driven by acceleration skewed (asymmetric) oscillatory flow with good agreement in the flow velocity, net sediment transport, and ripple migration rate. The model results showed that the asymmetric flow causes a net onshore sediment transport of both suspended and near-bed load (the conventional bed load and part of the near-bed suspended load, responsible for ripple migration). The suspended load transport is driven by the “positive phase-lag” effect, while the near-bed transport is due to the large erosion of the boundary layer on the stoss flank, sediment avalanching on the lee flank, and the returning flux induced by the stoss vortex. Together, these processes result in a net onshore transport rate. In contrast, for an energetic velocity skewed (skewed) flow, the net transport rate is offshore directed. This is due to a larger offshore-directed suspended load transport rate, resulting from the “negative phase-lag” effect, compared to the onshore-directed near-bed load transport rate. Compared to the asymmetric flow, the onshore near-bed load transport (and migration) rate is limited by the larger offshore directed flux associated with returning flow on the lee side, due to a stronger lee vortex generation during the onshore flow half-cycle. In the combined asymmetric-skewed case, the near-bed load and migration rate are higher than in the asymmetric flow case. Moreover, the offshore-directed suspended load is much smaller compared to the skewed flow case due to a competition between the negative (due to velocity skewness) and positive (due to acceleration skewness) phase-lag effects. As a result, the net transport rate is onshore directed but slightly smaller than the asymmetric flow case.
登录
查看更多内容
影响因子：
--
作者：
Marjolein Dohmen-Janssen;D. Hanes
通讯作者：
Marjolein Dohmen-Janssen;D. Hanes
影响因子：
4.6
作者：
Jabbari A;Ackerman JD;Boegman L;Zhao Y
通讯作者：
Zhao Y
影响因子：
--
作者：
Y. Chou;O. Fringer
通讯作者：
Y. Chou;O. Fringer
影响因子：
--
作者：
Jing Yuan;Dongxu Wang
通讯作者：
Jing Yuan;Dongxu Wang
振荡流产生的粗砂波纹的几何特征：全面的实验研究
影响因子：
4.4
作者：
Dongxu Wang;Jing Yuan
通讯作者：
Jing Yuan