Turbulent Flow Structures and Scour Hole Characteristics around Circular Bridge Piers over Non-Uniform Sand Bed Channels with Downward Seepage

In alluvial rivers bridge piers often cause local scour, a complex phenomenon as a result of the interaction between turbulent flow and bed material. In this paper, the results of an experimental study on the scour hole characteristics around single vertical pier sets on a non-uniform sand bed, unde...

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Bibliographic Details
Published inWater (Basel) Vol. 11; no. 8; p. 1580
Main Authors Chavan, Rutuja, Gualtieri, Paola, Kumar, Bimlesh
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 2019
Subjects
Alluvial channels
Alluvial rivers
Bed material
Bridge piers
Computational fluid dynamics
downward seepage
Empirical equations
Flow velocity
pier
Piers
Reynolds stress
Sand
Sand beds
Scour
Scouring
Sediment transport
Seepage
Sensors
Sound waves
Standard deviation
Turbulent flow
turbulent statistics
Vortices
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Summary:In alluvial rivers bridge piers often cause local scour, a complex phenomenon as a result of the interaction between turbulent flow and bed material. In this paper, the results of an experimental study on the scour hole characteristics around single vertical pier sets on a non-uniform sand bed, under no seepage, and with downward seepage conditions, are described. In case of downward seepage, turbulent statistics, such as Reynolds stress, higher order moments, TKE-flux, and consequently sediment transport, decrease upstream of the pier, while increasing on both sides of it, where the enhanced erosive capacity of the flow results in an increase in the scour hole width. Moreover, the scour hole length shifts downstream. Empirical equations for the evaluation of scour hole characteristics, such as the length, width, area, and volume, including the downward seepage parameter, are proposed and experimentally tested. Model predictions give reasonably good agreement with the experimental data.
ISSN:2073-4441
2073-4441
DOI:10.3390/w11081580