Author(s): Joshua D. Mortensen; Steven L. Barfuss; Blake P. Tullis

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Keywords: Air entrainment; characteristic length; closed conduit; hydraulic jump; location effect

Abstract: In vented closed conduit conveyance systems, air entrained through hydraulic jumps can be problematic for system operation. While various factors influencing air entrainment have been reported in the literature, no specific attention has been paid to the hydraulic jump location relative to the point of downstream air release. To better understand the effects of jump location on air entrainment, in this study, experiments were conducted in a vented, circular conduit with variable hydraulic jump locations relative to the pipe outlet. When the hydraulic jump was fully contained within the pipe, the air entrainment rate was dependent on the Froude number immediately upstream of the jump but was independent of the jump location within the pipe. The rate of air entrainment significantly increased, however, when the hydraulic jump was not fully contained within the pipe. For this condition, the distance from the toe of the jump to the pipe outlet significantly influences the air entrainment rate.

DOI: https://doi.org/10.1080/00221686.2012.670008

Year: 2012