Analysis of secondary current effect in the modeling of shallow flow in open channels

Song, Chang Geun; Seo, Il Won; Kim, Jae Won

doi:10.1016/j.advwatres.2012.02.003

Cited by 63 publications

(42 citation statements)

References 57 publications

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“…Shi et al [27] performed an LES in a smooth rectangular channel at a Reynolds number of approximately 90,000 and showed that LES allows very accurate predictions of turbulence statistics and boundary shear stress distributions are feasible. Some recent works show the potential of LES to describe the secondary flow patterns and turbulence statistics of curved open-channels (e.g., [28][29][30]). However, flow in bends exhibits different mechanics as the centripetal force contributes to the generation of spanwise motion (Prandtl's first kind [1]) together with the aforementioned turbulence anisotropy.…”

Section: Introductionmentioning

confidence: 99%

Secondary Currents and Turbulence over a Non-Uniformly Roughened Open-Channel Bed

Stoesser

McSherry

Fraga

2015

Water

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Large-eddy simulations (LES) of the flow over a non-uniformly roughened channel bed are carried out to study the effect of non-uniform bed roughness on turbulence driven secondary currents and turbulence statistics. The channel bed is comprised of alternating rough and smooth strips, the width of which corresponds to the water depth. The Reynolds number based on hydraulic radius and bulk velocity is 34,000. The LES are successfully validated using experimental data. The secondary flow and bed roughness have a significant effect on the streamwise velocity and second order turbulence statistics. Turbulence is enhanced over rough strips and suppressed over smooth strips. Significant lateral momentum transfer takes place due to both advection and turbulence. The bed shear stresses over the smooth strips are approximately four times less than over the rough strips a result of near bed low momentum fluid being transported from the rough strips to the smooth strips and high momentum fluid being convected from the surface towards the bed. The most significant terms in the streamwise momentum equation are quantified and discussed with regard to momentum transfer.

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Section: Introductionmentioning

confidence: 99%

Secondary Currents and Turbulence over a Non-Uniformly Roughened Open-Channel Bed

Stoesser

McSherry

Fraga

2015

Water

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“…The developed inundation model has its origins in river flow analysis models [14,15] that have been adapted for various situations [16][17][18]. …”

Section: Connection Of Underground Inundation In Two Layersmentioning

confidence: 99%

Numerical Computation of Underground Inundation in Multiple Layers Using the Adaptive Transfer Method

Rhee

Song

2018

Water

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Extreme rainfall causes surface runoff to flow towards lowlands and subterranean facilities, such as subway stations and buildings with underground spaces in densely packed urban areas. These facilities and areas are therefore vulnerable to catastrophic submergence. However, flood modeling of underground space has not yet been adequately studied because there are difficulties in reproducing the associated multiple horizontal layers connected with staircases or elevators. This study proposes a convenient approach to simulate underground inundation when two layers are connected. The main facet of this approach is to compute the flow flux passing through staircases in an upper layer and to transfer the equivalent quantity to a lower layer. This is defined as the 'adaptive transfer method'. This method overcomes the limitations of 2D modeling by introducing layers connecting concepts to prevent large variations in mesh sizes caused by complicated underlying obstacles or local details. Consequently, this study aims to contribute to the numerical analysis of flow in inundated underground spaces with multiple floors.

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“…Data from Blanckaert´s horizontal channel include water levels at the center of the channel with a reported roughness coefficient of 5x10 -6 m for the lateral walls and 0.003 m for the bottom [14]. Data from Rozovskii´s horizontal channel include water levels for the internal and external smooth walls and a roughness coefficient of 0.0004 m for the bottom [16,17]. Finally, data from Poggi's channel include water levels for the internal and external walls with longitudinal slopes of 5% and 10% [18].…”

Section: Experimental Data For Curved Channelsmentioning

confidence: 99%

“…Water depths in a curved channel measured by Han et al [12] were used for the calibration of the numerical parameters of the model (see channel geometry in Figure 2(a)); and water depths measured by Blanckaert, Rozovskii and Poggi [13][14][15][16][17][18] (see Figures 2(b), 2(c) and 2(d) for channels geometry) were used for validation. The flow characteristics and channel dimensions for each test case are presented in Table 1, (where B: channel width; h e : water depth at the channel entrance; h s : water depth at the channel exit; R m : mean radius of the channel; Q: discharge; θ: development angle of the channel curve; S o : longitudinal slope; L e : straight zone of the channel upstream the entrance; L s : straight zone downstream the exit).…”

Section: Experimental Data For Curved Channelsmentioning

confidence: 99%

See 1 more Smart Citation

New methodology for calibration of hydrodynamic models in curved open-channel flow

Gómez-Zambrano

López-Ríos

Toro-Botero³

2017

Rev. Fac. Ing. Univ. Antioquia

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This paper evaluates a new methodology for calibration of hydrodynamic models based on the theory of statistical design of experiments. An Eulerian-Eulerian hydrodynamic homogeneous model, integrated by the commercial software CFX Ansys Inc., is used to perform the numerical experiments. For the screening step, the fractional factorial experimental design 2 7-2 was used, followed by a Draper-Lin design of second order to find the optimum point in the calibration. A new method is introduced to generate the level of points to the center and to carry out the test of lack of fit. In this work, we develop a validated methodology for the calibration of deterministic hydrodynamic models with several factors, suggesting a second-order regression model for forecasting the optimum point of the simulations, with acceptable accuracy in predicting the response variable. RESUMEN:Se propone una nueva metodología para la calibración de modelos hidrodinámicos a partir de la aplicación del diseño estadístico de experimentos. Un modelo hidrodinámico Euleriano-Euleriano homogéneo se usa para realizar los experimentos numéricos, el cual está incorporado en el software comercial CFX de Ansys Inc. En la etapa de calibración se utiliza un diseño factorial fraccionado, 2 7-2 , seguido de un diseño Draper-Lin de segundo orden, para encontrar el punto óptimo de la calibración. Se introduce un nuevo método para generar los niveles de los puntos al centro necesarios para la realización de la prueba de falta de ajuste, logrando configurar una metodología validada para la calibración de modelos hidrodinámicos determinísticos con varios factores de entrada. Se logra un modelo de regresión de segundo orden para la predicción del punto óptimo de las simulaciones, con una aceptable precisión en la predicción de la variable de respuesta analizada. information provided is not enough to be applied directly to hydrodynamic simulation because it does not specify how to replicate points with numerical experimentation [3][4][5][6][7].To overcome this problem, the statistical theory of the lack of fit with no replications was used to generate the information for the neighbor points, treating them as the real points to the center [8,9]. Additionally, the descending scaling methodology was used to identify the points of minima outside the initial experimental region [1,2].The numerical simulations in this work were performed by an Eulerian-Eulerian hydrodynamic model for the conservation of mass and momentum laws. It was applied to a two-phase flow of water and air, in order to find the interface surface between these two fluids, which is useful

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Analysis of secondary current effect in the modeling of shallow flow in open channels

Cited by 63 publications

References 57 publications

Secondary Currents and Turbulence over a Non-Uniformly Roughened Open-Channel Bed

Secondary Currents and Turbulence over a Non-Uniformly Roughened Open-Channel Bed

Numerical Computation of Underground Inundation in Multiple Layers Using the Adaptive Transfer Method

New methodology for calibration of hydrodynamic models in curved open-channel flow

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