A Simple And General Subgrid Model Suitable Both For Surface Layer And Free-Stream Turbulence

Abstract. This paper deals with the characteristics of the atmospheric turbulent flow in the vicinity of the ground, and particularly with the profile of the horizontal wind variance. The study is based on experimental measurements performed with fast cup anemometers located near the ground at 5 different levels (from 0.25 to 4 m) and sampled at 1 Hz. The experiment was carried over two agricultural plots with various tillage treatments in a fallow semiarid area (Central Aragon, Spain). The results of this study reveal that near the ground surface and under moderate wind, the horizontal wind variance logarithmically increases with height, in direct relationship with the friction velocity and the roughness length scale. A theoretical development has allowed us to link this behaviour to the modeling of the turbulent kinetic energy (TKE) transport through the eddy diffusivity. Thus, the study proposes a formulation of the similarity universal function of the horizontal wind variance. Besides, the formulation offers a new method for the determination of the friction velocity and the roughness length scale and can be used for the evaluation of the TKE transport rate.

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“…Redelsperger et al (2001) showed that this relationship can be demonstrated. Their calculation led to a slightly different equation:…”

Section: Theoretical Backgroundmentioning

confidence: 92%

“…Combining some equations for the subgrid scheme and for similarity laws, Redelsperger et al (2001) deduced that the length scale L can be expressed as follows:…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Profile of the horizontal wind variance near the ground in near neutral flow – K-theory and the transport of the turbulent kinetic energy

Yahaya

Frangi

2009

Ann. Geophys.

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“…The Harlow-Nakayama closure model (see e.g. [15,30]) is a k -ε closure model commonly used in meteorology. In particular, it introduces a characteristic mixing length scale m , which, in the specific case of near-surface turbulence, depends on the vertical coordinate z (see [12,34]).…”

Section: Turbulence Closure Equations For Sdmmentioning

confidence: 99%

Stochastic Lagrangian method for downscaling problems in computational fluid dynamics

Bernardin¹,

Bossy²,

Chauvin³

et al. 2010

ESAIM: M2AN

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Abstract. This work aims at introducing modelling, theoretical and numerical studies related to a new downscaling technique applied to computational fluid dynamics. Our method consists in building a local model, forced by large scale information computed thanks to a classical numerical weather predictor. The local model, compatible with the Navier-Stokes equations, is used for the small scale computation (downscaling) of the considered fluid. It is inspired by Pope's works on turbulence, and consists in a so-called Langevin system of stochastic differential equations. We introduce this model and exhibit its links with classical RANS models. Well-posedness, as well as mean-field interacting particle approximations and boundary condition issues are addressed. We present the numerical discretization of the stochastic downscaling method and investigate the accuracy of the proposed algorithm on simplified situations.Mathematics Subject Classification. 65C20, 65C35, 68U20, 35Q30.

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“…The form of these exchange coefficients can vary, e.g. Louis (1979), Louis et al (1981), Cuxart et al (2000) and Redelsperger et al (2001). Such schemes rely on some closure assumptions such that their actual behaviour is only an approximation of reality.…”

Section: Introductionmentioning

confidence: 99%

On the role of tuning in parametrizations of unresolved diffusive processes in atmospheric models

Termonia

Smet

Bergh

2012

Quart J Royal Meteoro Soc

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A Simple And General Subgrid Model Suitable Both For Surface Layer And Free-Stream Turbulence

Cited by 60 publications

References 33 publications

Profile of the horizontal wind variance near the ground in near neutral flow – K-theory and the transport of the turbulent kinetic energy

Profile of the horizontal wind variance near the ground in near neutral flow – K-theory and the transport of the turbulent kinetic energy

Stochastic Lagrangian method for downscaling problems in computational fluid dynamics

On the role of tuning in parametrizations of unresolved diffusive processes in atmospheric models

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