Local Scour at Bridge Piers: The Role of Reynolds Number on Horseshoe Vortex Dynamics

Abstract

This paper reports a comprehensive study of the major scour agent around bridge piers: the turbulent horseshoe vortex . The intricate and inherently unsteady characteristics of the junction flow are captured within a series of scaled laboratory experiments. We applied the state-of-the art Time-Resolved Digital Particle Image Velocimetry (TR-DPIV) technique to measure the velocity field at the centerline plane of symmetry upstream of a cylindrical model. Three levels of Reynolds numbers (ReD) based on the obstacle diameter were studied: 26,000, 48,000 and 117,500. We evaluated the effect of this factor based on the time-averaged analyses of velocity and vorticity. Basic statistical analysis of the fluctuating velocity components provided insight to the physical mechanism that governs the behavior of the horseshoe vortex at the aforementioned levels of ReD.

Laboratory validation of buried piezoelectric scour sensing rods

“…Numerous factors can affect the rate and extent of this dynamic phenomenon, including support geometry, inclination, geometry, spacing, and group arrangements, as well as water depth, flow rate, angle of attack, and sediment properties. [2][3][4][5][6][7][8] If a large enough scour hole develops around the supports, the reduction of the axial and lateral capacity of the structure can lead to undesirable deflections, structural instability, or even failure. Scour is a major problem worldwide, including the United States [9] and many East-Asian countries that regularly experience typhoons and floods.…”

“…Scour is the removal of bed sediments from around the structure's supports by flowing water, especially during floods. Numerous factors can affect the rate and extent of this dynamic phenomenon, including support geometry, inclination, geometry, spacing, and group arrangements, as well as water depth, flow rate, angle of attack, and sediment properties . If a large enough scour hole develops around the supports, the reduction of the axial and lateral capacity of the structure can lead to undesirable deflections, structural instability, or even failure.…”

Reduction of Local Scour around Bridge Piers Using Different Countermeasures.(Dept.C)

“…Where R ep is Reynolds number based on pier width instead of water depth ( used by Apsilidis et al [14] and F r is the Froude number( . Various models of piers have been investigated to predict the depth of scour for each type.…”

“…EMPIRICAL RELATIONSHIPS Using Statistical Package for the Social Sciences (SPSS)program to generate relationships of different types of piers. Empirical relations were deduced between Froude number only with relative scour depth and relations between Froude number and Reynolds number based on pier width as used by Apsilidis et al[14] with relative scour depth shown in Tables(3,4).…”

“…): Comparison between calculated and measured relative scour depth for Upstream curved face Slotted oblong pier and two piles using Eqns (14). and (20)…”