A detached eddy simulation model for the study of lateral separation zones along a large canyon‐bound river

Alvarez, L. V.; Schmeeckle, M. W.; Grams, Paul E.

doi:10.1002/2016jf003895

Cited by 29 publications

(35 citation statements)

References 84 publications

(101 reference statements)

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“…Further, the fluctuated velocities illustrated the phenomenon of eddy pulsation, also observed by Alvarez et al. () who used the DES model to study the flow in a sharp bend of the Colorado River in the United States. The time series indicated a cycle of low frequencies of velocities over the 100 to 150 s recurrence interval for both the streamwise and transverse velocities in Figure a,b.…”

Section: Resultssupporting

confidence: 69%

“…It is noteworthy that Alvarez et al. () utilized the DES modelling technique to study the turbulence, sediment transport and sandbar beach failure process in the Colorado River, USA. Thus, it was deemed feasible to apply the DES model to study the turbulence in natural rivers using the supercomputer cluster.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, DES is actually a hybrid technique combining the merits of RANS for near riverbed areas and LES in the flow interior (Constantinescu, Miyawaki, & Rhoads, 2011;Zhang, Liang, & Liu, 2016;Zhang, Ye, & Stanev, 2016), highlighting the relatively lower computational costs compared to the LES models. The DES model has been applied to study river confluence flows (Constantinescu et al, 2011), free surface flows (Zhang, Liang et al, 2016;Zhang, Ye et al, 2016) and sediment transport (Alvarez, Schmeeckle, & Grams, 2017) in idealized or laboratory flumes. It is noteworthy that Alvarez et al (2017) utilized the DES modelling technique to study the turbulence, sediment transport and sandbar beach failure process in the Colorado River, USA.…”

Section: Introductionmentioning

confidence: 99%

“…The DES model has been applied to study river confluence flows (Constantinescu et al, 2011), free surface flows (Zhang, Liang et al, 2016;Zhang, Ye et al, 2016) and sediment transport (Alvarez, Schmeeckle, & Grams, 2017) in idealized or laboratory flumes. It is noteworthy that Alvarez et al (2017) utilized the DES modelling technique to study the turbulence, sediment transport and sandbar beach failure process in the Colorado River, USA. Thus, it was deemed feasible to apply the DES model to study the turbulence in natural rivers using the supercomputer cluster.…”

Section: Introductionmentioning

confidence: 99%

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Using an eddy‐resolving technique to assess the effects of reservoir operation on the bend flow in Yangtze River, China

Wang

Zhou

et al. 2019

Lakes & Reservoirs

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With increasing computing power over the last decade, eddy‐resolving methods in hydraulics engineering have been widely used to investigate the turbulence structure in natural rivers, where accurate field measurements were difficult to conduct and investigate. A detached eddy simulation (DES) model was developed on the basis of the k‐ω‐SST (shear stress transport) eddy‐viscosity model within the framework of an unstructured‐mesh Semi‐implicit Eulerian–Lagrangian Finite Element (SELFE) hydrodynamic model. The DES model was then applied to simulate the bend flow in the upper Yangtze River, and the calculation efficiency was enhanced through parallelized computation to mitigate the high computation costs involved in the DES modelling. The time‐averaged velocity, turbulent intensity and Reynolds stress were compared, using DES modelling and acoustic Doppler current profiler (ADCP) measuring results, indicating good agreement, especially in the near‐bed region. The coupled relationship between the turbulent flow and riverbed terrain was also investigated through extracting and analysing the high‐order statistical variables reflecting the turbulence structure, including non‐hydrostatic pressure, vorticity and helicity, indicating the fluctuated amplitude of non‐hydrostatic pressure can reach to 100 Pa, and the stripe distribution of non‐hydrostatic pressure and vorticity had an orthogonality relation. At the same time, the streamwise velocity at the middle of the HLM bend was found to be decreased at least 0.7 m/s because of unsteady process smoothing and backwater effects attributable to water releases and storage of the reservoirs located upstream and downstream of the HLM bend. The developed unstructured‐mesh DES model will provide a new tool to study turbulent flows in a natural river and assess the effect of reservoir operations on river flows.

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Section: Resultssupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Using an eddy‐resolving technique to assess the effects of reservoir operation on the bend flow in Yangtze River, China

Wang

Zhou

et al. 2019

Lakes & Reservoirs

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“…Dinehart and Burau, 2005;Kasvi et al, 2013;Vermeulen et al, 2014aVermeulen et al, , 2015Engel and Rhoads, 2016;Knox and Latrubesse, 2017;Kasvi et al, 2017;Lotsari et al, 2017;Parsapour-Moghaddam and Rennie, 2018), junctions (e.g. Venditti et al, 2014;Alvarez et al, 2017;Tomas et al, 2018), deltas (e.g. Parsons et al, 2007;Szupiany et al, 2012), canyons (e.g.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of aDcp processing options for secondary flow identification at river junctions

Moradi

Vermeulen

Rennie

et al. 2019

Earth Surf Processes Landf

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Secondary circulation in river confluences results in a spatial and temporal variation of fluid motion and a relatively high level of morphodynamic change. Acoustic Doppler current profiler (aDcp) vessel‐mounted flow measurements are now commonly used to quantify such circulation in shallow water fluvial environments. It is well established that such quantification using vessel‐mounted aDcps requires repeated survey of the same cross‐section. However, less attention has been given to how to process these data. Most aDcp data processing techniques make the assumption of homogeneity between the measured radial components of velocity. As acoustic beams diverge with distance from the aDcp probe, the volume of the flow that must be assumed to be homogeneous between the beams increases. In the presence of secondary circulation cells, and where there are strong rates of shear in the flow, the homogeneity assumption may not apply, especially deeper in the water column and close to the bed. To reduce dependence on this assumption, we apply a newly‐established method to aDcp data obtained for two medium‐sized (~60–80 m wide) gravel‐bed river confluences and compare the results with those from more conventional data processing approaches. The comparison confirms that in the presence of strong shear our method produces different results to more conventional approaches. In the absence of a third set of fully independent data, we cannot demonstrate conclusively which method is best, but our method involves less averaging and so in the presence of strong shear is likely to be more reliable. We conclude that it is wise to apply both our method and more conventional methods to identify where data analysis might be impacted upon by strong shear and where inferences of secondary circulation may need to be made more cautiously. © 2019 John Wiley & Sons, Ltd.

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Sand settling through bedform‐generated turbulence in rivers

Yuill

Wang

Meselhe

et al. 2020

Earth Surf Processes Landf

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Fluvial bedforms generate a turbulent wake that can impact suspended-sediment settling in the passing flow. This impact has implications for local suspended-sediment transport, bedform stability, and channel evolution; however, it is typically not well-considered in geomorphologic models. Our study uses a three-dimensional OpenFOAM hydrodynamic and particle-tracking model to investigate how turbulence generated from bedforms and the channel bed influences medium sand-sized particle settling, in terms of the distribution of suspended particles within the flow field and particle-settling velocities. The model resolved the effect of an engineered bedform, which altered the flow field in a manner similar to a natural dune. The modelling scenarios alternated bed morphology and the simulation of turbulence, using detached eddy simulation (DES), to differentiate the influence of bedform-generated turbulence relative to that of turbulence generated from the channel bed. The bedform generated a turbulent wake that was composed of eddies with significant anisotropic properties. The eddies and, to a lesser degree, turbulence arising from velocity shear at the bed substantially reduced settling velocities relative to the settling velocities predicted in the absence of turbulence. The eddies tended to advect sediment particles in their primary direction, diffuse particles throughout the flow column, and reduced settling likely due to production of a positively skewed vertical-velocity fluctuation distribution. Study results suggest that the bedform wake has a significant impact on particle-settling behaviour (up to a 50% reduction in settling velocity) at a scale capable of modulating local suspended transport rates and bedform dynamics.

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A detached eddy simulation model for the study of lateral separation zones along a large canyon‐bound river

Cited by 29 publications

References 84 publications

Using an eddy‐resolving technique to assess the effects of reservoir operation on the bend flow in Yangtze River, China

Using an eddy‐resolving technique to assess the effects of reservoir operation on the bend flow in Yangtze River, China

Evaluation of aDcp processing options for secondary flow identification at river junctions

Sand settling through bedform‐generated turbulence in rivers

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