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Title: Self-aerated flow on Corps of Engineers spillways
Authors: St. Anthony Falls Hydraulic Laboratory.
Environmental Laboratory (U.S.)
Water Quality Research Program (U.S.)
Wilhelms, Steven C.
Gulliver, John S.
Keywords: Air entrainment
Free surface
Gas transfer
Water quality
Hydraulic structures
Publisher: Hydraulics Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Description: Technical Report
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.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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