Self-Aerated Flow on Corps of Engineers Spillways

Abstract

Air entrainment in free-surface spillway flows is described with two concepts: 'entrained air,' which is air being transported by the flow as bubbles, and 'entrapped air,' which is the air transported with the flow in the roughness of the water surface. Results from flume experiments are used to develop a mathematical description of entrained and entrapped air for flow along a spillway face. Observations from a full-scale spillway validate the procedure. The theory of gas transfer shows how entrained air affects gas transfer with large increases in the interfacial area. A bubble-size distribution, based on photographic analyses, was used to estimate the surface area in self-aerated flow. Previous experimental work defined the minimum air concentration to prevent cavitation damage at approximately 8 percent. The location along the spillway now can be estimated where entrained air at the spillway surface reaches this concentration. Air entrainment, Gas transfer, Cavitation, Spillway, Free surface

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Document Details

Document Type
Technical Report
Publication Date
May 01, 1994
Accession Number
ADA284890

Entities

People

  • John S. Gulliver
  • Steven C. Wilhelms

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Air Entrainment
  • Boundary Layer
  • Civil Engineering
  • Engineering
  • Engineers
  • Entrainment
  • Fluid Dynamics
  • Fluid Flow
  • Fluid Mechanics
  • Mass Transfer
  • Reynolds Number
  • Roughness
  • Surface Roughness
  • Turbulence
  • Turbulent Boundary Layer
  • Turbulent Mixing
  • Water Quality

Readers

  • Combustion and Flow Dynamics.
  • Hydraulic Engineering.
  • Underwater engineering and Marine Technology.