Universal scaling-law for flow resistance over canopies with complex morphology

Rubol, S.; Ling, Bowen; Battiato, Ilenia

doi:10.1038/s41598-018-22346-1

Cited by 44 publications

(38 citation statements)

References 64 publications

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“…While a great deal of progress in understanding the role of weak thermal stratification with surface-to-bottom temperature differentials of 1-4 • C has been made [5,[16][17][18][19][20][21][22], future studies are suggested to address the effects of diverse macrophytes commonly occupying a large portion of water on temperature and circulation dynamics in shallow lakes. The development of models that account for various vegetation types, such as floating-leaved and free-floating plants [88], are highly desired to represent their impact on drag and light attenuation conditions. This type of study requires high-fidelity hydrodynamic modeling in a real lake environment, in which flow motions in horizontal and vertical dimensions might be equally significant.…”

Section: Discussionmentioning

confidence: 99%

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

Torma

2019

Water

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In this paper, the effects of littoral submerged macrophytes on weak stratification conditions in a small and shallow lake are investigated. Diverse submerged macrophytes occupying a large portion of the littoral zone act as resistance to water motions and affect lake hydrodynamics. Strong solar radiation and mild wind forcing typically occurring during the summer season result in weak stratification characterized by a diurnal cycle with a temperature differential of 1-3 • C. Temperature and circulation dynamics of a small and shallow lake are depicted by extensive field measurements and a three-dimensional non-hydrostatic model with a generic length scale (GLS) approach for the turbulence closure and drag forces induced by macrophytes. Results show that the effects of macrophytes on velocity profiles are apparent. In the pelagic area, the circulation patterns with and without macrophytes are similar. The velocity profile is generally characterized by a two-layer structure with the maximum velocity at both the water surface and the mid-depth. In contrast, inside the littoral zone, the mean flow is retarded by macrophytes and the velocity profile is changed to only one maximum velocity at the surface with a steeper decrease until 2.0 m depth and another slight decrease to the lake bottom. From the whole lake perspective, littoral macrophytes dampen the horizontal water temperature difference between the upwind side and download side of the lake. Macrophytes promote a stronger temperature stratification by retarding mean flows and reducing vertical mixing. Overall, this study shows that the temperature structures and circulation patterns under weak stratification conditions in a small and shallow lake are strongly affected by littoral vegetation.

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Section: Discussionmentioning

confidence: 99%

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

Torma

2019

Water

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“…The approach from Battiato and Rubol (2014), developed for submerged vegetation, follows the concept of coupling an incompressible fluid flow with a porous medium flow. Although it is conceptually suited for rigid vegetation, this approach was also successfully validated with flexible vegetation (see Rubol et al, 2018). The main advantage of this approach lies in the representation of the drag force by a single parameter, i.e.…”

Section: Battiato and Rubolmentioning

confidence: 99%

Uncertainty quantification of floodplain friction in hydrodynamic models

Dalledonne

Kopmann

Brudy-Zippelius

2019

Hydrol. Earth Syst. Sci.

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Abstract. This study proposes a framework to estimate the uncertainty of hydrodynamic models on floodplains. The traditional floodplain resistance formula of Pasche (1984) (based on Lindner, 1982) used for river modelling as well as the approaches of Baptist et al. (2007), Järvelä (2004), and Battiato and Rubol (2014) was considered for carrying out an uncertainty quantification (UQ). The analysis was performed by means of three different methods: traditional Monte Carlo (MC), first-order second-moment (FOSM) and metamodelling. Using a two-dimensional hydrodynamic model, a 10 km reach of the River Rhine was simulated. The model was calibrated with water level measurements under steady flow conditions and then the analysis was carried out based on flow velocity results. The compared floodplain friction formulae produced qualitatively similar results, in which uncertainties in flow velocity were most significant on the floodplains. Among the tested resistance formulae the approach from Järvelä (2004) presented on average the smallest prediction intervals, i.e. the smallest variance. It is important to keep in mind that UQ results are not only dependent on the defined input parameter deviations, but also on the number of parameters considered in the analysis. In that sense, the approach from Battiato and Rubol (2014) is still attractive for it reduces the current analysis to a single parameter, the canopy permeability. The three UQ methods compared gave similar results, which means that FOSM is the less expensive one. Nevertheless it should be used with caution as it is a first-order method (linear approximation). In studies involving dominant non-linear processes, one is advised to carry out further comparisons.

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“…Moreover, additional experiments were carried out in the case of dense canopy. These specific conditions were tested in order to understand difference between models based on Darcy-Brinkman equation (Rubol et al, 2018) and those with a turbulent drag force (Klopstra et al 1997;Meijer and Velzen 1999;Cassan and Laurens 2016).…”

Section: Introductionmentioning

confidence: 99%

Flow over Flexible Vegetated Bed: Evaluation of Analytical Models

Romdhane

Soualmia

Cassan

et al. 2019

JAFM

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The development of vegetation in the river bed and in the banks can affect the hydrodynamic conditions and the flow behavior of a watercourse. This can increase the risk of flooding and sediment transport. Therefore, it is important to develop analytical approaches to predict the resistance caused by vegetation and model its effect on the flow. This is the objective of this work which investigates the ability of different analytical models to predict the vertical velocity profile as well as the resistance induced by flexible submerged vegetation in open channels. Then it is possible to select the appropriate model that will be applied in the real case of rivers. The model validation is determined after a comparison between the data measured in the different experiments carried out and those from literature. For dense vegetation, the role of the Reynolds number is emphasized in particular with a model using the Darcy-Brinkman equation in the canopy. With a simple permeability, this model is relevant to estimate friction. However, for larger Reynolds number, models based on the fully turbulent flow assumption provide better results.

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Universal scaling-law for flow resistance over canopies with complex morphology

Cited by 44 publications

References 64 publications

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

Uncertainty quantification of floodplain friction in hydrodynamic models

Flow over Flexible Vegetated Bed: Evaluation of Analytical Models

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