On the Laws of Resistance to Turbulent Flow in Open Smooth Channels

Abstract

It is generally considered that differing from the pipe flow, the flow in open channels has a free surface and waves appearing on water surface relate to some extent with .the laws of resistance on turbulent flow in open channels. According to the above opinion, instability of flow is connected with the mixing length of turbulence; and computing the velocity distribution by Prandtl's equation which expresses the flow near the wall, Froude Number is introduced with Reynolds Number in the laws of reistance on turbulent flow in open channels. Applying this theory, experimental results by authors, Dr. Matuo and R. W. Powell with smooth open channels can be explained within the region of sub- and supercritical flow, and, therefore, the difference between the laws of resistance to turbulent flow in pipes and that in open channels can be made clear.