Effect of spur dike length on the horseshoe vortex system and the bed shear stress distribution

Köken, Mete; Göğüş, Mustafa

doi:10.1080/00221686.2014.967819

Cited by 35 publications

(15 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Considering the abutment protrusion ratios and flow conditions, they explained that the velocities near an abutment are magnified up to 1.5 times the approach flow velocity, and the shear stresses are enlarged up to 10 times the approach bed shear stress. Koken and Gogus [16] studied the effect of spur dike length on bed shear stress distribution. They found that the large bed shear stress values and pressure standard deviation values observed around the tip of the spur dike, beneath the upstream part of the main horseshoe vortex and beneath the separated shear layers, increase with increasing spur dike length.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Influence of Spur Dikes Spacing on Local Scour and Flow

Ning

2019

Applied Sciences

View full text Add to dashboard Cite

The spacing of spur dikes is an important consideration for the layout of spur dike channels. This study focuses on the local scour morphology and flow field characteristics of spur dikes with different spacings. The results show that the maximum scour depth is generally found in the vicinity of the first spur dike head. With the increase of the spacing of spur dikes, the shielding effect of the first spur dike is weakened. The maximum velocity in the main flow zone is twice that of the approach flow velocity in the fixed bed. But it is approximately the same as the incoming velocity in equilibrium scouring. The maximum turbulent energy appears to be mainly located in the backflow area of the fourth spur dike in the fixed bed, while the maximum value appears at the second spur dike head in the movable bed. Further, the shear stress decreases as scouring develops. Pearson correlation analysis was carried out between scour depth and shear stress. The analysis results are significantly correlated, indicating that the bed shear stress plays a prominent role in the scouring process. These discoveries can serve as a guide to determine the most reasonable spacing of spur dikes.

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Influence of Spur Dikes Spacing on Local Scour and Flow

Ning

2019

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…Same as experiment the vertical coordinate and the radial distance will be normalized by l=D/2. Different from the previous cylinder pier case, horseshoe vortex system around the semicircular abutment is not developed very well as has been pointed out by Gogus [38]. Therefore, it is reasonable to anticipate that scour in this case should primarily be driven by the bed shear-layers that sheds from the nose of the abutment and locally increases at the lee side.…”

Section: Semicircular Bridge Abutmentmentioning

confidence: 91%

Simulations of Local Scour Around a Cylindrical Bridge Pier And a Semicircular Abutment Using Unsteady k-ε Model Combined with σ-Grid

Shi¹,

Yang²,

Wu³

2017

TOCIEJ

View full text Add to dashboard Cite

Introduction:Bridge scour is one of the major causes of bridge failure. Prediction of the maximum depth and shape of local scour plays an important role in bridge design and maintenance. In this paper, k-ε turbulent model combined with wall function was employed and complex flow fields are exhibited. The bed load transport model summarized by Qian and Wan [1] was applied to evaluate the development of local scour. Besides, σ-grid module was developed and embedded into the commercial solver FLUENT to fit the change of channel-bed. Method:In this module, the change of the elevation of the channel bed is calculated through using user defined functions(UDF), and the motion of the grid system is realized based on a program developed through C++ language, which extends the applications of FLUENT. The evolution of local scour hole for two cases, i.e., local scour around a cylindrical pier and a semicircular abutment, was simulated. Results and Conclusion:The depth and the shape of local scour as well as the flow fields were predicted. Numerical result conforms well to the experimental measurement. Especially, it provides fairly reasonable prediction on the key issue of the maximum scour depth. The satisfactory agreement validates the numerical method developed in the present study. In addition to the validation purpose, the different performance of this method for predicting local scour around the cylindrical pier and the semicircular abutment was discussed.

show abstract

“…The morphology dynamics, including scour and deposition at the toe of submerged rigid engineering structures, such as engineering deflectors, have attracted substantial research. Most of this research has focused on the developing process of local scour and the local flow pattern [5][6][7][8], the scour depth and the scour volume [9][10][11], the temporal development of scour hole [12], and the sediment deposition features [13].…”

Section: Introductionmentioning

confidence: 99%

Local Scour Near Flexible Flow Deflectors

Xie

Zhu

Huang

et al. 2020

Water

View full text Add to dashboard Cite

Rigid flow deflectors are usually used on water flow beds to protect engineering structures such as breakwater in coasts and to regulate flow routes in open channels. To reduce its side-effects, i.e., local scour at the toe of deflectors, a flexible flow deflector is proposed, and the corresponding local scour was investigated in this study. A flume experiment was conducted to investigate local scour. To show the advantage of flexible deflectors, a control experimental test was also conducted using a traditional rigid deflector under the same blockage area configuration and the same flow conditions. The flow field near the flexible deflector was also measured to reveal the local flow field. The results show that the bed-scour develops near the toe edges of both flexible and rigid deflectors, but the maximum and averaged scour depths for the flexible deflector are smaller. This advantage of flexible deflector in scour depth is mainly caused by its prone posture, which induces the upward stretching and enlarging horizontally rotating vortex and the upward shifted vertically rotating vortex. The former dissipates more turbulent energy and the latter results in smaller bed shear stress, which lead to smaller scour depth directly. In addition, the up- and down-swaying movement of the flexible deflector can also assistant to dissipate more turbulent energy, thereby damping the intense of the horseshoe vortices and thus weakening scour depth as well. The results of this study provide an elementary understanding on the mechanisms of a flexible flow structure and an alternative deflector-device to reduce scour depth.

show abstract

Effect of spur dike length on the horseshoe vortex system and the bed shear stress distribution

Cited by 35 publications

References 19 publications

Numerical Simulation of the Influence of Spur Dikes Spacing on Local Scour and Flow

Numerical Simulation of the Influence of Spur Dikes Spacing on Local Scour and Flow

Simulations of Local Scour Around a Cylindrical Bridge Pier And a Semicircular Abutment Using Unsteady k-ε Model Combined with σ-Grid

Local Scour Near Flexible Flow Deflectors

Contact Info

Product

Resources

About