Influence of Channel Aspect Ratio and Curvature on Flow, Secondary Circulation, and Bed Shear Stress in a Rectangular Channel Bend
Influence of Channel Aspect Ratio and Curvature on Flow, Secondary Circulation, and Bed Shear Stress in a Rectangular Channel Bend
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DOI：
10.1061/(asce)hy.1943-7900.0000643
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发表时间：
2012-11
影响因子：
2.4
通讯作者：
S. Kashyap;G. Constantinescu;C. Rennie;G. Post;R. Townsend
中科院分区：
文献类型：
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作者：
S. Kashyap;G. Constantinescu;C. Rennie;G. Post;R. Townsend
冲积河道弯曲水流受河道几何形状的影响很大，包括曲率比（弯曲半径/河道宽度，R/B）和长宽比（河道宽度/水流深度，B/H）。高曲率弯管（R/B≤3）可能比曲率较低的弯管遭受更多的腐蚀。本文采用三维雷诺平均Navier-Stokes（RANS）模型研究了135°弯曲中大曲率（R/B=1.5）情况下曲率比和展弦比对弯曲流动的影响。实验数据被用来验证RANS模型预测的高曲率基本情况下，一个平床（FB）和平衡变形床（DB）。五个曲率比（1.5，3，5，8和10）和四个纵横比（5.00，6.67，9.09和12.50）进行了研究。结果表明，在FB情况下，R/B或B/H的减小导致与横流环流的主环流圈（Γ+）有关的区域的总环流强烈增加，最大环流圈增加。
AbstractFlow within an alluvial channel bend is significantly affected by channel geometry, including curvature ratio (bend radius/channel width, R/B) and aspect ratio (channel width/flow depth, B/H). High curvature bends (R/B≤3) can experience substantially more erosion than milder curvature bends. This study employs a three-dimensional Reynolds-Averaged Navier-Stokes (RANS) model to investigate the effects of curvature ratio and aspect ratio on bend flow with respect to a high curvature (R/B=1.5) base case in a 135° bend. Experimental data are used to validate the RANS model predictions for the high curvature base case with a flat bed (FB) and an equilibrium deformed bed (DB). Five curvature ratios (1.5, 3, 5, 8, and 10) and four aspect ratios (5.00, 6.67, 9.09, and 12.50) are investigated. Results show that a decrease in R/B or B/H for the FB cases results in a strong increase in total circulation of the regions associated with the primary cell of cross-stream circulation (Γ+), an increase in maximum b...