Air injection for scour reduction

Document Type

Conference Proceeding

Publication Date

5-31-2018

Department

Department of Civil, Environmental, and Geospatial Engineering

Abstract

Scour at hydraulic structures such as bridge piers and abutments, stilling basins, and river bends can cause loss of life, structural collapse, and environmental damage to the ecosystem. Although many passive (requiring no greenhouse emitting use of electricity) scour countermeasures exist, such as riprap, submerged vanes, collars, spur dikes, sills, and sacrificial piles, these are subject to local scour and destruction themselves. An alternative flow-altering scour countermeasure consisting of air injection into the scour-inducing flow pattern can have benefits. Air injection cannot cause local scour due to the flow-adjusting nature of the bubbles since they are not rigid. Although injecting air does require an air compressor, it can be powered by solar panels and set up to only be activated during high-flows. Air injection is not needed in low-flows since the water velocity is slow and below the scour incipient motion conditions. Air injection has been proven successful in laboratory experiments for stilling basins and cylindrical bridge piers. Scour is reduced by the uplifting of the flow by the rising bubbles and the lowering of turbulence by the bubbles.

Publisher's Statement

© ASCE 2018. Publisher’s version of record: https://doi.org/10.1061/9780784481424.008

Publication Title

World Environmental and Water Resources Congress 2018

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