Analytical Eddy Viscosity Model for Velocity Profiles in the Outer Part of Closed- and Open-Channel Flows

Absi, Rafik

doi:10.1134/s0015462821040017

Cited by 5 publications

(2 citation statements)

References 28 publications

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“…Figure (6) presents the friction factor as a function of the Reynolds number obtained by the law of-the-wall method. This result is compared to DNS data and the recalibrated Dean's correlation.…”

Section: Law-of-the-wall Methodsmentioning

confidence: 99%

“…This represents an ideal theoretical framework and is related to most of the industrial applications. It was already studied experimentally [28] [30], theoretically, and numerically [22] [14][15] [27] [9] [1][2][3][4][5][6][7][8]. Currently, "direct numerical simulation" (DNS) provides accurate results [26] [20] [19] which are used extensively to evaluate and validate the different proposed relations.…”

Section: Introductionmentioning

confidence: 99%

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Friction factor from velocity profiles in smooth turbulent channel flows

et al. 2022

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Additive manufacturing is in clear progress in the field of civil engineering construction, essentially boosting by the development of new information and communication technologies. For better industrialization of the use of this technique, in-situ control of products manufactured along the production line is a major issue. In this work we were able to supervise the quality of printed object along the process by comparing the target values and those measured by image processing obtained by a camera installed in the printing device. We have developed a program that allows us to measure the deformations of the different layers and thus to assess the difference between the values of the target ratings and those achieved. This deviation is defined as a criterion for validating piece conformity and can also be used to adapt the process parameters.

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Section: Law-of-the-wall Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Friction factor from velocity profiles in smooth turbulent channel flows

et al. 2022

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Comments on «Modeling stratified suspension concentration distribution in turbulent flow using fractional advection–diffusion equation» by Snehasis Kundu, environmental fluid mechanics, https://doi.org/10.1007/s10652-019–09,679-9

Absi

2021

Environ Fluid Mech

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Suspended Sediments in Environmental Flows: Interpretation of Concentration Profiles Shapes

Absi

2022

Hydrology

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In environmental flows, field and laboratory measurements of suspended sediments show two kinds of concentration profiles. For coarse sediments, a near-bed upward convex profile is observed beneath the main upward concave profile. In this study, we consider two 1-DV models, namely, the classical advection–diffusion equation (ADE) based on the gradient diffusion model, and the kinetic model. Both need sediment diffusivity, which is related to the eddy viscosity, and an y-dependent β-function (i.e., the inverse of the turbulent Schmidt number). Our study shows that the kinetic model reverts to the classical ADE with an “apparent” settling velocity or sediment diffusivity. For the numerical resolution of the ADE, simple and accurate tools are provided for both the sediment diffusivity and hindered settling. The results for the concentration profiles show good agreement with the experimental data. An interpretation of the concentration profiles is provided by two “criteria” for shapes. The main for steady open-channel flows shows that the shape of the concentration profiles in the Cartesian coordinate depends on the vertical distribution of the derivative of R (the ratio between the sediment diffusivity and the settling velocity of the sediments): dR/dy > −1 for the upward concave concentration profile while dR/dy < −1 for the near-bed upward convex profile. A generalization is proposed for oscillatory flows over sand ripples, where the time-averaged concentration profiles in the semi-log plots are interpreted by a relation between the second derivative of the logarithm of the concentration and the derivative of the product between the sediment diffusivity and an additional parameter related to the convective sediment entrainment process.

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Analytical Eddy Viscosity Model for Velocity Profiles in the Outer Part of Closed- and Open-Channel Flows

Cited by 5 publications

References 28 publications

Friction factor from velocity profiles in smooth turbulent channel flows

Friction factor from velocity profiles in smooth turbulent channel flows

Comments on «Modeling stratified suspension concentration distribution in turbulent flow using fractional advection–diffusion equation» by Snehasis Kundu, environmental fluid mechanics, https://doi.org/10.1007/s10652-019–09,679-9

Suspended Sediments in Environmental Flows: Interpretation of Concentration Profiles Shapes

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