Effect of Viscosity on the Equilibrium Scour Depth at Single Cylindrical Piers

Lança, Rui; Simarro, Gonzalo; Fael, Cristina; Cardoso, António H.

doi:10.1061/(asce)hy.1943-7900.0001102

Cited by 17 publications

(11 citation statements)

References 4 publications

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“…According to Melville and Chiew [68], D/d 50 should be larger than 50. Sheppard et al [69], Lee and Sturm [70], and Lança et al [71] , where, b is the channel width) on scour has been frequently treated as a minor issue when D/b is less than ten percent [72]. New evidence has suggested that the influence of D/b on scour also depends on D/d 50 , where for D/d 50 > 100, this effect seems to amplify [73].…”

Section: Physical Modelling and Controlling Scour Parametersmentioning

confidence: 99%

The Science behind Scour at Bridge Foundations: A Review

Pizarro

Manfreda

Tubaldi

2020

Water

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Foundation scour is among the main causes of bridge collapse worldwide, resulting in significant direct and indirect losses. A vast amount of research has been carried out during the last decades on the physics and modelling of this phenomenon. The purpose of this paper is, therefore, to provide an up-to-date, comprehensive, and holistic literature review of the problem of scour at bridge foundations, with a focus on the following topics: (i) sediment particle motion; (ii) physical modelling and controlling dimensionless scour parameters; (iii) scour estimates encompassing empirical models, numerical frameworks, data-driven methods, and non-deterministic approaches; (iv) bridge scour monitoring including successful examples of case studies; (v) current approach for assessment and design of bridges against scour; and, (vi) research needs and future avenues.

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Section: Physical Modelling and Controlling Scour Parametersmentioning

confidence: 99%

The Science behind Scour at Bridge Foundations: A Review

Pizarro

Manfreda

Tubaldi

2020

Water

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“…At equilibrium conditions,  and S approach   and   , respectively. Hence, combining equations (4), (7) and (12) one obtains…”

Section: Theoretical Frameworkmentioning

confidence: 99%

“…Equation 2). Figure 1(a) reports     vs  as estimated using the experimental data in [6,12] assuming b=5. This dataset was chosen as it spans a wide range of .…”

Section: Empirical Testmentioning

confidence: 99%

“…The experimental data in [6,12], [13] and [14] are now exploited to empirically derive the function      via Equation (15). This experimental dataset refers to cylindrical piers with circular cross section, uniform non-cohesive sediments, steady flows and large B/a ratios (more details about the experimental data can be found in MB15).…”

Section: Empirical Testmentioning

confidence: 99%

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Viscosity effects on local scour around vertical structures in clear-water conditions

et al. 2018

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Local scour represents the erosion process that occurs at the base of hydraulic structures overlying sediment beds. Horseshoe vortices forming at the bed-structure junction are the main responsible for sediment removal and dictate erosion rates as well as the maximum erosion depth resulting from a significant flow event. In steady-flow conditions this is often referred to as the equilibrium scour depth, which, for many hydraulic structures, represents a key parameter for foundation-design and risk-assessment purposes. The equilibrium scour depth has been investigated for decades and many predictive formulae have been developed following the classical empirical approach, whereby numerous experimental datasets are used to isolate and identify the influence of non-dimensional groups emerging from dimensional analysis. Within this context, the influence of obstacle Reynolds numbers, and consequently of viscous forces, has always been neglected because of the large Re values normally encountered in engineering and laboratory conditions. The present paper demonstrates that this assumption is largely incorrect especially for beds made of sand or finer material. The theoretical analysis presented in Manes and Brocchini ([1]) is herein extended to include viscosity effects and investigate their importance on equilibrium scour depths forming around obstacles resembling bridge piers.

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“…The Reynolds number varied between 18,300 and 38,300 implying that viscous effects could be overlooked [31].…”

Section: Figure 3 -Pier Shapes Used In Experiments (All Dimensions Armentioning

confidence: 99%

Experimental Investigation of Scour Hole Characteristics for Different Shapes of Piers Caused by Flood Hydrograph Succeeding Steady Flow

Türkben

Güney

2021

Teknik Dergi

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In this study, the scour depth and dimensions of the scour hole around different shaped piers in the case of hydrographs succeeding steady flow were studied experimentally. The experiments were carried out by using circular, square, rectangular, lenticular and rectangular with trapezoidal nose to compare the various scour hole geometries at the same flow conditions. Numerous experiments were conducted in a rectangular flume (18.6 m long, 0.80 m wide and 0.75 m deep) with different triangular shaped hydrographs. The flume bed of 26 cm thickness consists of uniform graded material with D 50 =1.68 mm. The experiments were carried out in clear water conditions. The temporal variations of the equilibrium scour depths in front of the pier and the scour hole dimensions were recorded by two different cameras. The equilibrium scour depths at lateral sides and downstream of the piers were also measured. Regression analysis was performed in order to derive empirical relations to predict temporal variations of the scour depth in the case of unsteady flow. The shape factor values were also investigated based on the experimental findings and the obtained values were compared with those available in literature. The performance of the obtained empirical relation for circular pier was tested by using limited experimental data available in the literature. The smallest scour hole was observed for the rectangular with trapezoidal noses pier. The increase in the scour hole dimensions for other cross-sections was in the following order: rectangular with circular noses, circular, square and rectangular piers.

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Effect of Viscosity on the Equilibrium Scour Depth at Single Cylindrical Piers

Cited by 17 publications

References 4 publications

The Science behind Scour at Bridge Foundations: A Review

The Science behind Scour at Bridge Foundations: A Review

Viscosity effects on local scour around vertical structures in clear-water conditions

Experimental Investigation of Scour Hole Characteristics for Different Shapes of Piers Caused by Flood Hydrograph Succeeding Steady Flow

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