Abstract

Based on Navier-Stokes’ equation, a theoretical analysis is performed for the characteristics of flow resistance for uniform flows both in open channel and in pipe. It is shown that there are obvious differences between open channel flows and pipe flows in resistance of per unit mass of water. Therefore the difference of resistance characteristics exists between the two kinds of flow. The experimental data show that the concept of full rough region of turbulent flow (resistance square region) cannot be applied to explain some phenomena in uniform flow of open channels. So the theory, turbulent flow can be divided into three regions, as established by Nikuradse’s experimental research may not be applicable for open channel flow. The influence of Reynolds number should be taken into account in the investigation of resistance and turbulent characteristics for open channel flow.

Keywords: open channel flow, pipe flow, flow resistance, turbulent characteristics