Numerical Simulation of Coherent Structures over Plant Canopy

Gavrilov, K.A.; Accary, Gilbert; Morvan, Dominique; Lyubimov, D. V.; Méradji, Sofiane; Bessonov, Oleg

doi:10.1007/s10494-010-9294-z

Cited by 32 publications

(22 citation statements)

References 37 publications

(61 reference statements)

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“…Several studies have attempted to study the nature of turbulence across a roughness transition such as a grassland and a forest canopy by means of experimental and numerical methods (Li et al, 1990;Peltola, 1996;Irvine et al, 1997;Belcher et al, 2003;Yang et al, 2006;Cassiani et al, 2008;Detto et al, 2008;Dupont and Brunet, 2009;Dalpe and Masson, 2009;Fesquet et al, 2009;Gavrilov et al, 2010Gavrilov et al, , 2011Huang et al, 2011;Rominger and Nepf, 2011;Schlegel et al, 2012;Banerjee et al, 2013;Chatziefstratiou et al, 2014;Markfort et al, 2014;Kanani-Sühring and Raasch, 2015;Queck et al, 2016;Kröniger et al, 2017) and documented several length scales associated with the roughness transitions, recirculation zones and the nature of the turbulent momentum budget. However, all of these studies are concerned with the flow adjustment in the immediate vicinity of the roughness transition (edges or gaps).…”

Section: Introductionmentioning

confidence: 99%

Turbulent transport of energy across a forest and a semiarid shrubland

et al. 2018

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Abstract. The role of secondary circulations has recently been studied in the context of well-defined surface heterogeneity in a semiarid ecosystem where it was found that energy balance closure over a desert-forest system and the structure of the boundary layer was impacted by advection and flux divergence. As a part of the CliFF ("Climate feedbacks and benefits of semi-arid forests", a collaboration between KIT, Germany, and the Weizmann Institute, Israel) campaign, we studied the boundary layer dynamics and turbulent transport of energy corresponding to this effect in Yatir Forest situated in the Negev Desert in Israel. The forest surrounded by small shrubs presents a distinct feature of surface heterogeneity, allowing us to study the differences between their interactions with the atmosphere above by conducting measurements with two eddy covariance (EC) stations and two Doppler lidars. As expected, the turbulence intensity and vertical fluxes of momentum and sensible heat are found to be higher above the forest compared to the shrubland. Turbulent statistics indicative of nonlocal motions are also found to differ over the forest and shrubland and also display a strong diurnal cycle. The production of turbulent kinetic energy (TKE) over the forest is strongly mechanical, while buoyancy effects generate most of the TKE over the shrubland. Overall TKE production is much higher above the forest compared to the shrubland. The forest is also found to be more efficient in dissipating TKE. The TKE budget appears to be balanced on average both for the forest and shrubland, although the imbalance of the TKE budget, which includes the role of TKE transport, is found to be quite different in terms of diurnal cycles for the forest and shrubland. The difference in turbulent quantities and the relationships between the components of TKE budget are used to infer the characteristics of the turbulent transport of energy between the desert and the forest.

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Section: Introductionmentioning

confidence: 99%

Turbulent transport of energy across a forest and a semiarid shrubland

et al. 2018

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“…Attempts to model the interaction between the atmosphere and tall canopies are usually based on simplified vegetation structures (e.g., Shaw and Patton 2003;Yang et al 2006a;Cassiani et al 2008;Dupont and Brunet 2008;Sogachev et al 2008;Gavrilov et al 2010;Huang et al 2011;Dupont et al 2011;Banerjee et al 2013;Kanani-Sühring and Raasch 2015). Particular investigations of the small-scale horizontal inhomogeneity have shown the importance of detailed information on vegetation structure (e.g., Albertson et al 2001;Bohrer et al 2009).…”

Section: Introductionmentioning

confidence: 99%

The TurbEFA Field Experiment—Measuring the Influence of a Forest Clearing on the Turbulent Wind Field

Queck

Bernhofer

Bienert

et al. 2016

Boundary-Layer Meteorol

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Forest ecosystems play an important role in the interaction between the land surface and the atmosphere. Measurements and modelling efforts have revealed significant uncertainties in state-of-the-art flux assessments due to spatial inhomogeneities in the airflow and land surface. Here, a field experiment is used to describe the turbulent flow across a typical Central European forest clearing. A three-dimensional model of the inhomogeneous forest stand was developed using an innovative approach based on terrestrial laser-scanner technology. The comparison of the wind statistics of two measurement campaigns (5 and 12 months long) showed the spatial and temporal representativeness of the ultrasonic anemometer measurements within the canopy. An improved method for the correction of the vertical velocity enables the distinction between the instrumental offsets and the vertical winds due to the inclination of the instrument. Despite a 13 % fraction of deciduous plants within the otherwise evergreen canopy, the effects of phenological seasons on the velocity profiles were small. The data classified according to the wind speed revealed the intermittent nature of recirculating air in the clearing. Furthermore, the development of sub-canopy wind-speed maxima is explained by considering the velocity moments and the momentum equation (including measurements of the local pressure gradient). Clearings deflect the flow downward and feed the sub-canopy flow, i.e., advective fluxes, according to wind speed and, likely, clearing size, whereas local pressure gradients play an important role in the development of sub-canopy flow. The presented dataset is freely available at the project homepage.

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“…The coupled flows have been studied since 1950s [1][2][3][4][5][6][7]. The problem has many applications in the environmental science and technology: contaminant transport in the rivers and atmosphere [8,9], solidification of the liquid metals [10][11][12], heat and mass transfer between the contacting media [13], optimization of the flows in the fuel cells [5], etc.…”

Section: Introductionmentioning

confidence: 99%

Verification of the boundary condition at the porous medium–fluid interface

Tsiberkin

Kolchanova

Lyubimova

2016

EPJ Web of Conferences

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We study the hydrodynamic stability of liquid flowing down over the inclined layer of uniform porous medium and compare the results obtained in the different frameworks. The flow in porous medium is described by the Brinkman model and by the Darcy model with corresponding boundary conditions at the interface between the homogeneous fluid and porous medium. It is shown the critical Reynolds number is calculated for the Darcy model much lower than in case of the Brinkman model, while the flow velocity is the same in the both models. It is a pure mathematical effect, which can be used to verify the models and to determine the empirical coefficients in the boundary conditions from an experimental study of flow instability.

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Numerical Simulation of Coherent Structures over Plant Canopy

Cited by 32 publications

References 37 publications

Turbulent transport of energy across a forest and a semiarid shrubland

Turbulent transport of energy across a forest and a semiarid shrubland

The TurbEFA Field Experiment—Measuring the Influence of a Forest Clearing on the Turbulent Wind Field

Verification of the boundary condition at the porous medium–fluid interface

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