Two-phase modeling of suspended sediment distribution in open channel flows

Jiang, Junsheng; Law, Adrian Wing‐Keung; Cheng, Nian‐Sheng

doi:10.1080/00221686.2004.9728392

Cited by 13 publications

(15 citation statements)

References 23 publications

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“…However, it is important to numerically calculate the results with this theory. Starting from a two-phase flow theory, Greimann et al [10] and Jiang et al [11] derived analytical solutions of velocity lag, but their solutions were confined to verification with limited experimental data. Cheng [12] presented a model of velocity lag, based on a hindered drag force in sediment-laden flow and stated that the model may not be well applicable when the velocity and concentration gradients were significant in the flow.…”

Section: Introductionmentioning

confidence: 99%

Entropy-Based Modeling of Velocity Lag in Sediment-Laden Open Channel Turbulent Flow

Kumbhakar

Kundu

Ghoshal

et al. 2016

Entropy

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Abstract:In the last few decades, a wide variety of instruments with laser-based techniques have been developed that enable experimentally measuring particle velocity and fluid velocity separately in particle-laden flow. Experiments have revealed that stream-wise particle velocity is different from fluid velocity, and this velocity difference is commonly known as "velocity lag" in the literature. A number of experimental, as well as theoretical investigations have been carried out to formulate deterministic mathematical models of velocity lag, based on several turbulent features. However, a probabilistic study of velocity lag does not seem to have been reported, to the best of our knowledge. The present study therefore focuses on the modeling of velocity lag in open channel turbulent flow laden with sediment using the entropy theory along with a hypothesis on the cumulative distribution function. This function contains a parameter η, which is shown to be a function of specific gravity, particle diameter and shear velocity. The velocity lag model is tested using a wide range of twenty-two experimental runs collected from the literature and is also compared with other models of velocity lag. Then, an error analysis is performed to further evaluate the prediction accuracy of the proposed model, especially in comparison to other models. The model is also able to explain the physical characteristics of velocity lag caused by the interaction between the particles and the fluid.

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Section: Introductionmentioning

confidence: 99%

Entropy-Based Modeling of Velocity Lag in Sediment-Laden Open Channel Turbulent Flow

Kumbhakar

Kundu

Ghoshal

et al. 2016

Entropy

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“…Their formula showed that velocity lag decreases towards the free surface of open-channel flow. A similar two-phase analysis of the velocity lag was carried out by Jiang et al [13]. Based on the drag force on a sediment particle in the presence of other neighbors, Cheng [1] analytically derived the expression for velocity lag by relating the hindrance coefficient to the shear stress distribution in uniform sediment-laden open-channel flows.…”

Section: Introductionmentioning

confidence: 83%

An Expression for Velocity Lag in Sediment-Laden Open-Channel Flows Based on Tsallis Entropy Together with the Principle of Maximum Entropy

Zhu

Dou

et al. 2019

Entropy

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In the context of river dynamics, some experimental results have shown that particle velocity is different from fluid velocity along the stream-wise direction for uniform sediment-laden open-channel flows; this velocity difference has been termed velocity lag in the literature. In this study, an analytical expression for estimating the velocity lag in open-channel flows was derived based on the Tsallis entropy theory together with the principle of maximum entropy. The derived expression represents the velocity lag as a function of a non-dimensional entropy parameter depending on the average and maximum values of velocity lag from experimental measurements. The derived expression was tested against twenty-two experimental datasets collected from the literature with three deterministic models and the developed Shannon entropy-based model. The Tsallis entropy-based model agreed better with the experimental datasets than the deterministic models for eighteen out of the twenty-two total real cases, and the prediction accuracy for the eighteen experimental datasets was comparable to that of the developed Shannon entropy-based model (the Tsallis entropy-based expression agreed slightly better than the Shannon entropy-based model for twelve out of eighteen test cases, whereas for the other six test cases, the Shannon entropy-based model had a slightly higher prediction accuracy). Finally, the effects of the friction velocity of the flow, the particle diameter, and the particles’ specific gravity on the velocity lag were analyzed based on the Tsallis entropy-based model. This study shows the potential of the Tsallis entropy theory together with the principle of maximum entropy to predict the stream-wise velocity lag between a particle and the surrounding fluid in sediment-laden open-channel flows.

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“…The vertical turbulent intensity 0 2 my u    can be determined by invoking turbulence models for two-phase mixtures. In this study, as has been adopted in previous studies for the sake of simplicity [3,4,6,26,27], we resorted to a modified version of the empirical relation proposed by Nezu and Rodi [28] …”

Section: Inertia Effect On Vertical Sediment Diffusion For Steady Andmentioning

confidence: 99%

Particle inertia effect on sediment dispersion in turbulent open-channel flows

Zhang

Zhong

Wang

2014

Sci. China Technol. Sci.

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Particle inertia effect plays a significant role in sediment dispersion which has not been fully elucidated. In this paper, the profound effect of particle inertia on the sediment dispersion was analyzed. The theoretical expression for the drift velocity based on the two-phase mixture theory in turbulent open channels is firstly introduced. The influence of particle inertia on sediment dispersion was investigated through three different aspects including vertical dispersion, motion, and flux properties based on the drift velocity. Results show that the dispersion of suspended sediment in turbulent open-channel flows is affected by three major processes including turbulence of water sediment mixtures, particle random motion, and collisions among particles, of which the contributions of particle turbulence and collisions to the sediment dispersion are remarkable for particles of high inertia. With respect to the vertical mean velocity and sediment flux, it shows that the predictive results agree well with the measurements when the term of particle inertia is considered. As a result, particle inertia considerably affects the behavior of suspended sediment. In particular, the influence of inertia must be accounted for in circumstances of flows laden with high-inertia particles. inertia, effect, suspended sediment, dispersion Citation: Zhang L, Zhong D Y, Wu B S. Particle inertia effect on sediment dispersion in turbulent open-channel flows.

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Two-phase modeling of suspended sediment distribution in open channel flows

Cited by 13 publications

References 23 publications

Entropy-Based Modeling of Velocity Lag in Sediment-Laden Open Channel Turbulent Flow

Entropy-Based Modeling of Velocity Lag in Sediment-Laden Open Channel Turbulent Flow

An Expression for Velocity Lag in Sediment-Laden Open-Channel Flows Based on Tsallis Entropy Together with the Principle of Maximum Entropy

Particle inertia effect on sediment dispersion in turbulent open-channel flows

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