Physical Modeling to Determine Head Loss at Selected Surcharged Sewer Manholes

by K. H. Wang,
T. G. Cleveland,
C. Towsley,
D. Umrigar,

Document Type: Proceeding Paper

Part of: North American Water and Environment Congress & Destructive Water


The head losses at sewer pipe junctions (manholes) under surcharged conditions were measured in a 1:6 scale model of a typical manhole with one main line passing through it and two perpendicular lateral lines flowing into it. Head-loss coefficients were determined for a variety of outlet-flow Reynolds number, surcharge level, pipe configurations and size, and inlet-flow contribution. Empirical formulas were also developed to estimate head-loss coefficients. The results indicate that head loss is insensitive to the amount of surcharge, but heavily depends on the flow configuration, relative flow rate, and pipe size ratio. The head loss becomes significant in the manhole junctions when there exists lateral inflows or the junction forces a change in direction. For many inlet flow conditions, the manhole loss is equivalent to 200–400 extra feet of pipe.

Subject Headings: Head loss (fluid mechanics) | Manholes | Head (fluid mechanics) | Scale models | Sewers | Physical models | Pipe sizes | Sewer pipes

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