Threshold Criteria for Incipient Grain Motion with Turbulent Fluctuations on a Horizontal Bed

Mohtar, Wan Hanna Melini Wan

doi:10.17576/jsm-2015-4401-20

Cited by 4 publications

(2 citation statements)

References 25 publications

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“…To study the role of different sinusoidal shapes of the channels on the flow variations and the bed morphology in meandering rivers, they carried out their experiments in curved channels with fixed walls and movable bed. Mohtar [14] studied the effect of turbulent fluctuations and vortices on the sediment incipient motion. Their results implied a constant Shields parameter in the flow region having a rigid bed.…”

Section: Introductionmentioning

confidence: 99%

Effect of Mean Velocity to Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

Moghaddassi¹,

Musavi-Jahromi²,

Vaghefi³

et al. 2021

Preprint

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As 180-degree meanders are observed in abundance in nature, a meandering channel with two consecutive 180-degree bends was designed and constructed to investigate bed topography variations. These two 180-degree mild bends are located between two upstream and downstream straight paths. In this study, different mean velocity to critical velocity ratios have been tested at the upstream straight path to determine the meander's incipient motion. To this end, bed topography variations along the meander and the downstream straight path were addressed for different mean velocity to critical velocity ratios. In addition, the upstream bend's effect on the downstream bend has been investigated. Results indicated that the maximum scour depth at the downstream bend has increased as a result of changing the mean velocity to critical velocity ratio from 0.8 to 0.84, 0.86, 0.89, 0.92, 0.95, and 0.98 by respectively 1.5, 2.5, 5, 10, 12, and 26 times. Moreover, increasing the ratio increased the maximum sedimentary height by 3, 10, 23, 48, 49, and 56 times. The upstream bend's incipient motion was observed for the mean velocity to critical velocity ratio of 0.89, while the downstream bend was equal to 0.78.

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Section: Introductionmentioning

confidence: 99%

Effect of Mean Velocity to Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

Moghaddassi¹,

Musavi-Jahromi²,

Vaghefi³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…To study the role of different sinusoidal shapes of the channels on the flow variations and the bed morphology in meandering rivers, they carried out their experiments in curved channels with fixed walls and a movable bed. Mohtar [14] studied the effect of turbulent fluctuations and vortices on the sediment incipient motion. Their results implied a constant Shields parameter in the flow region having a rigid bed.…”

Section: Introductionmentioning

confidence: 99%

Effect of Mean Velocity-to-Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

Moghaddassi

Musavi-Jahromi

Vaghefi

et al. 2021

Water

View full text Add to dashboard Cite

As 180-degree meanders are observed in abundance in nature, a meandering channel with two consecutive 180-degree bends was designed and constructed to investigate bed topography variations. These two 180-degree mild bends are located between two upstream and downstream straight paths. In this study, different mean velocity-to-critical velocity ratios have been tested at the upstream straight path to determine the meander’s incipient motion. To this end, bed topography variations along the meander and the downstream straight path were addressed for different mean velocity-to-critical velocity ratios. In addition, the upstream bend’s effect on the downstream bend was investigated. Results indicated that the maximum scour depth at the downstream bend increased as a result of changing the mean velocity-to-critical velocity ratio from 0.8 to 0.84, 0.86, 0.89, 0.92, 0.95, and 0.98 by, respectively, 1.5, 2.5, 5, 10, 12, and 26 times. Moreover, increasing the ratio increased the maximum sedimentary height by 3, 10, 23, 48, 49, and 56 times. The upstream bend’s incipient motion was observed for the mean velocity-to-critical velocity ratio of 0.89, while the downstream bend’s incipient motion occurred for the ratio of 0.78.

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Laboratory analysis of incipient motion velocity for non-uniform non-cohesive sediments movement in rectangular flumes

2015

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Threshold Criteria for Incipient Grain Motion with Turbulent Fluctuations on a Horizontal Bed

Abstract: The effect of turbulent fluctuations on the threshold criteria for incipient grain motion over a wide range of sediment size is investigated. In this work, attention is paid to the comparison of the critical Shields parameter

Cited by 4 publications

References 25 publications

Effect of Mean Velocity to Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

Effect of Mean Velocity to Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

Effect of Mean Velocity-to-Critical Velocity Ratios on Bed Topography and Incipient Motion in a Meandering Channel: Experimental Investigation

Laboratory analysis of incipient motion velocity for non-uniform non-cohesive sediments movement in rectangular flumes

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