Turbulent open-channel flow in circular corrugated culverts

This paper presents the results of a laboratory study of the velocity field in turbulent open-channel flow in a circular corrugated pipe of diameter D of 0.622 m for three slopes S of 0.55, 1.14, and 2.55% and a range of disc harges from 30 to 200 L/s. The Manning n was found to be equal to 0.023. Ve locities were relatively small in some portion of the flow near the boundar y of the pipe, and these low velocity regions may be useful for fish passag e upstream. In the region of fully developed flow, in the central vertical plane, the longitudinal velocity u was described by the Prandtl equation fo r rough turbulent flow, with a dip in the velocity profiles near the water surface. The velocity profiles in the noncentral planes were also described by the Prandtl equation for rough turbulent flow, but with a significant d ip in the upper part of the flow. An empirical method was devised to descri be the geometrical and kinematical properties of this velocity dip. The gen eral findings of this study were also found to be valid for flow in a large corrugated pipe of diameter of 4.27 m with two slopes of 0.14 and 1.42%.