MODELING MIXED FLOW IN STORM SEWERS

The blowing off of storm manhole covers may be attributed to the severe pressure transients that can occur during and after the transition from free-surface to pressurized flow in a sewer system. Observations from a physical sewer model with a submerged outlet indicate that the pressure transients were composed of an initial flow frequency water hammer type pressure surge and a subsequent high frequency pressure fluctuation caused by the release of trapped air at the upstream manhole. A mathematical model, which was based on the assumption of rigid water columns and a compressible air bubble, was derived to simulate the pressure transients. The frequency of pressure transients predicted by the calibrated mathematical model is in close agreement with that recorded during the laboratory experiments. The attenuation of the pressure fluctuations, however, is underestimated. This may be attributed to the superposition of various air release processes observed during the experiments and the assumption of a steady-state friction factor used in the mathematical model.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/8672558
• Corporate Authors:

  American Society of Civil Engineers

  1801 Alexander Bell Drive
  Reston, VA  United States  20191-4400
• Authors:
  • Li, Jian
  • 0000-0003-3439-7539
  • McCorquodale, A
• Publication Date: 1999-11

Language

• English

Media Info

• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: p. 1170-80
• Serial:
  • Journal of Hydraulic Engineering
  • Volume: 125
  • Issue Number: 11
  • Publisher: American Society of Civil Engineers
  • ISSN: 0733-9429
  • Serial URL: https://ascelibrary.org/journal/jhend8

Subject/Index Terms

• TRT Terms: Attenuation (Engineering); Calibration; Experiments; Flow; Free surface; Friction factor; Laboratory studies; Manholes; Mathematical models; Pressurization; Steady state; Storm sewers; Transients
• Subject Areas: Highways; Hydraulics and Hydrology; I26: Water Run-off - Freeze-thaw;

Filing Info

• Accession Number: 00779613
• Record Type: Publication
• Files: TRIS
• Created Date: Dec 7 1999 12:00AM