Formula for friction factor in open channel

摘要

This paper concerns variations of the friction factor for open channel in the two transitional regimes, one between laminar and turbulent flow and the other between above regime and fully rough turbulent flow. By deploying Guo's logarithmic matching method and interpolation approach, this note develops a single explicit formula for computing the friction factor in all flow regimes. The results obtained for open channel give a better representation of Zegshda's experimental data.