Experimental study on the variation mechanism of velocity correction
coefficient of overland flow
Abstract
The velocity correction coefficient is the key to calculate the mean
velocity of overland flow, which is a parameter of slope soil erosion
process model. Therefore, this paper systematically studied the
variation mechanism of the correction coefficient under 5 kinds of
slope, 5 kinds of flow rate, 5 kinds of roughness, 9 kinds of gravel
coverage and 3 kinds of rainfall intensity conditions based on fixed-bed
resistance and simulated rainfall test. The results showed that the
relationship between the coefficient and the slope was the inverse
function, and its influence on the correction coefficient was weak when
the slope was steeper than 10°; both Reynolds number and rainfall
intensity could promote the increase of correction coefficient; the
relationship between correction coefficient and the submergence degree
was in the form of logarithm function, which was alos the same as
Reynolds number, but the response of the correction coefficient to both
was just opposite. The research results provide the theoretical basis
for the accurate selection of velocity correction coefficient, which has
important theoretical and practical significance for the investigation
of soil erosion power and sediment carrying mechanism of overland flow
related to the mean velocity.