Preliminary study of the interference of surface objects and rainfall in overland flow resistance

CATENA ◽  
2009 ◽  
Vol 78 (2) ◽  
pp. 154-158 ◽  
Author(s):  
Gary Li
Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1657
Author(s):  
Jingzhou Zhang ◽  
Shengtang Zhang ◽  
Si Chen ◽  
Ming Liu ◽  
Xuefeng Xu ◽  
...  

To explore the characteristics of overland flow resistance under the condition of sparse vegetative stem coverage and improve the basic theoretical research of overland flow, the resistance characteristics of overland flow were systematically investigated under four slope gradients (S), seven flow discharges (Q), and six degrees of vegetation coverage (Cr). The results show that the Manning roughness coefficient (n) changes with the ratio of water depth to vegetation height (h/hv) while the Reynolds number (Re), Froude number (Fr), and slope (S) are closely related to vegetation coverage. Meanwhile, h/hv, Re, and Cr have strong positive correlations with n, while Fr and S have strong negative correlations with n. Through data regression analysis, a power function relationship between n and hydraulic parameters was observed and sensitivity analysis was performed. It was concluded that the relationship between n and h/hv, Re, Cr, Q, and S shows the same law; in particular, for sparse stem vegetation coverage, Cr is the dominant factor affecting overland flow resistance under zero slope condition, while Cr is no longer the first dominant factor affecting overland flow resistance under non-zero slope condition. In the relationship between n and Fr, Cr has the least effect on overland flow resistance. This indicates that when Manning roughness coefficient is correlated with different hydraulic parameters, the same vegetation coverage has different effects on overland flow resistance. Therefore, it is necessary to study overland flow resistance under the condition of sparse stalk vegetation coverage.


2021 ◽  
Vol 603 ◽  
pp. 126862
Author(s):  
A. Nicosia ◽  
C. Di Stefano ◽  
V. Pampalone ◽  
V. Palmeri ◽  
V. Ferro

2000 ◽  
Author(s):  
Aaron Schen ◽  
Lisa X. Xu

Abstract The thermal regulation of tissue is controlled by the sympathetically mediated redistribution of cardiac output and change in local flow resistance of arterioles. The diameter change of the vessel from its resting level is governed by the state of the contractile proteins in vascular smooth muscle which can be influenced by the concentration of free cytosolic calcium ([Ca2+]i) in the vascular endothelial cells (Falcone, 1995).


2015 ◽  
Vol 12 (5) ◽  
pp. 1145-1156 ◽  
Author(s):  
Chen Ye ◽  
Xing-nian Liu ◽  
Xie-kang Wang

Geomorphology ◽  
1995 ◽  
Vol 13 (1-4) ◽  
pp. 71-86 ◽  
Author(s):  
Ian P. Prosser ◽  
William E. Dietrich ◽  
Janelle Stevenson

1972 ◽  
Vol 98 (3) ◽  
pp. 429-446
Author(s):  
David L. Schreiber ◽  
Donald L. Bender

1973 ◽  
Vol 99 (9) ◽  
pp. 1625-1627
Author(s):  
David L. Schreiber ◽  
Donald L. Bender

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaona Liu ◽  
Dengxing Fan ◽  
Xinxiao Yu ◽  
Ziqiang Liu ◽  
Jiamei Sun

AbstractTo quantify the hydraulic characteristics of overland flow on gravel-covered slopes, eight flow discharges (Q) (8.44–122 L/min), five slope gradients (J) (2°–10°) and four gravel coverage degrees (Cr) (0–30%) were examined via a laboratory flume. The results showed that (1) gravel changed flow regime. Gravel increased the Reynolds number (Re) by 2.94–33.03%. Re were less affected by J and positively correlated with Cr and Q. Gravel decreased the Froude number (Fr) by 6.83–77.31%. Fr was positively correlated with Q and J and negatively correlated with Cr. (2) Gravel delayed the flow velocity (u) and increased the flow depth (h) and flow resistance (f). Gravel reduced u by 1.20–58.95%. u was positively correlated with Q and J and negatively correlated with Cr. Gravel increased h by 0.12–2.41 times. h was positively correlated with Q and Cr and negatively correlated with J. Gravel increased f by 0.15–18.42 times. f were less affected by J, positively correlated with Cr and negatively correlated with Q. (3) The relationships between hydraulic parameters and Q, J and Cr identified good power functions. Hydraulic parameters were mainly affected by Cr. These results can guide the ecological construction of soil and water conservation.


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