2024 Volume 12 Issue 2 Article ID: 23-16165
A numerical simulation of a uniform flow in an open channel under wind stress conditions was performed to investigate the wind effect on the surface velocity and the sub-surface velocity profile, which is of interest in river-discharge measurements. The results of the open-channel flow show that the surface velocity and the sub-surface profile are more sensitive to wind stress as the bed friction velocity is smaller and the water depth is larger. It is also found that the magnitude of the surface drift velocity in the open channel increases monotonically with the ratio of the wind stress to the bed shear stress and reaches a maximum of 3–4% of the wind speed. This fact suggests that the wind speed correction factor in the discharge measurement should be estimated considering hydraulic and wind conditions rather than a constant value. The surface drift velocity obtained by several river observations may include not only the drift current but also other unknown effects.
