Effects of vegetation stem coverage on the hydraulic characteristics and on-wall and jet flow proportions at the gully head
| 第一作者： |
Lou, Yibao |
| 英文第一作者： |
Lou, Yibao |
| 联系作者： |
Wang, WenLong |
| 英文联系作者： |
Wang, WenLong |
| 发表年度： |
2023 |
| 卷： |
229 |
| 摘要： |
Vegetation in the upstream area played a critical role in influencing runoff processes and subsequent headcut erosion at the gully head. However, it remains unclear how the vegetation stem coverage affects the hydraulic parameters and the on-wall and jet flow characteristics at the gully head. A simulation flow scouring experiment was performed to explore the influences of the vegetation stem coverage (5 levels) on the hydraulic parameters and on-wall and jet flow proportions at the gully head under inflow discharges ranging from 3.6-9.6 m3 h-1. The results indicated that the runoff in the upstream area occurred in the supercritical turbulent flow regime, and its velocity decreased while the Manning roughness coefficient and Darcy-Weisbach coefficient increased with increasing vegetation stem diameter. The runoff velocity at the gully brink decreased with increasing vegetation stem diameter and increased as a linear function of the inflow discharge (R2 = 0.849-0.997). With increasing vegetation stem diameter, the proportion of on-wall flow increased, and the proportion of jet flow decreased. The on-wall and jet flow proportions ranged from 7% to 92% and 8% to 93%, respectively, under inflow discharges from 3.6-9.6 m3 h 1, thereby attaining the highest correlation with the runoff velocity, Reynolds number, and runoff kinetic energy and following a significant logarithmic function. The vegetation stem influences the hy-draulic parameters of the upstream area and gully head and thus influences the on-wall/jet flow proportion. This study could help elucidate the effect of vegetation on the hydraulic mechanism of headcut erosion and provide a theoretical foundation for improving gully headcut erosion models. |
| 刊物名称： |
CATENA |
| 参与作者： |
Lou,Yibao[1];Kang,Hongliang[4];Wang,WenLong[1],[2],[3],[7];Guo,Mingming[5];Zhu,Yanan[1];Feng,Lanqian[2],[3];Shi,Qianhua[6];Guo,Wenzhao[1];Xu,Wenxiu[1] |
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