摘要详情
455 / 2024-03-21 13:56:14
On the role of Froude number in turbulent flow and sediment transport through boulder arrays
Numerical simulation
摘要录用
In mountainous rivers, Froude number (Fr) in the vicinity of large boulders varies significantly at low relative submergence, leading to local hydraulic jumps. Yet few studies quantify the turbulent structures within these jumps and elucidate their impact on sediment transport. This research employs large eddy simulations to investigate the free-surface turbulent flow through boulder arrays placed over five layers of spheres. Three identical turbulent structures are observed, i.e., meandering high-speed streaks from the boulder’s corridor with a characteristic length of 3.6 folds of boulder diameter (D) at low Fr, flapping of boulder wakes with a length of 0.9D at intermittent Fr, and a "V"-shaped elongated-titling vortex structure with a length of 0.86D at high Fr. In the former two scenarios, the surface-subsurface flow exchanges govern drag and lift forces on bed spheres. While at high Fr, the "V"-shaped vortices emerge as the primary influencing factor. Considering these two mechanisms, the predicted deposition zones shift from upstream of boulders at low Fr to the flanks of boulders at high Fr. Additionally, the predicted scouring zones transition from the sides of the boulders to the wake region with increasing Fr. The deposition and scouring zones align well with experimental observations published in the literature, providing valuable insights into the inter-connection between sediment transport and flow structures.
重要日期
-
会议日期
10月14日
2024
至10月17日
2024
-
09月30日 2024
初稿截稿日期
-
10月17日 2024
注册截止日期
主办单位
国际水利与环境工程学会亚太地区分会
承办单位
长江水利委员会长江科学院
四川大学
四川大学
联系方式
- Congress Secretariat
- se******@iahr-apd2024.com
- +86*********
