Effects of increased geometric complexity on the comparison between computational and experimental simulations

Byrne, C. E. I.; Holdo̸, A. E.

doi:10.1016/s0167-6105(97)00284-5

Cited by 11 publications

(9 citation statements)

References 2 publications

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“…The choice of a k-closure model was made because the transport equations are relatively easy to parameterize and to initialize from atmospheric measurements. One weakness of such a model has been stressed by Byrne and Holdo (1998) and recently Riddle et al (2004) who both found the k-model to overpredict turbulent kinetic energy dissipation for simulations with no buildings. But, as argued in Hanna et al (2004), a large number of obstacles (such as in the MUST array) should produce their own turbulent kinetic energy and compensate for this weakness of the model.…”

Section: Turbulence Modelmentioning

confidence: 99%

Numerical simulations of pollutant dispersion in an idealized urban area, for different meteorological conditions

Milliez

Carissimo

2006

Boundary-Layer Meteorol

108

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In order to estimate the impacts of buildings on air pollution dispersion, numerical simulations are performed over an idealized urban area, modelled as regular rows of large rectangular obstacles. The simulations are evaluated with the results of the Mock Urban Setting Test (MUST), which is a near full-scale experiment conducted in Utah's West Desert area: it consists of releases of a neutral gas in a field of regularly spaced shipping containers. The numerical simulations are performed with the model Mercure_Saturne, which is a three-dimensional computational fluid dynamics code adapted to atmospheric flow and dispersion simulations. It resolves complex geometries and uses, in this study, a k-closure for the turbulence model. Sensitivity studies focus on how to prescribe the inflow conditions for turbulent kinetic energy. Furthermore, different sets of coefficients available in the literature for the k-closure model are tested. Twenty MUST trials with different meteorological conditions are simulated and detailed analyses are performed for both the dynamical variables and average concentration. Our results show overall good agreement according to statistical comparison parameters, with a fraction of predictions for average concentration within a factor of two of observations of 67.1%. The set of simulations offers several inflow wind directions and allows us to emphasize the impact of elongated buildings, which create a deflection of the plume centerline relative to the upstream wind direction.

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Section: Turbulence Modelmentioning

confidence: 99%

Numerical simulations of pollutant dispersion in an idealized urban area, for different meteorological conditions

Milliez

Carissimo

2006

Boundary-Layer Meteorol

108

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“…However, this work employed a uniform velocity proÿle at the inlet boundary with no attempt to model the turbulence, which would be present in a real life application. Modelling of turbulence and shear at in ow boundaries has also been demonstrated to be important even when using two-equation type turbulence models [5]. This has prompted the current Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Simulations of high‐aspect‐ratio jets

Holdo̸

Simpson

2002

Numerical Methods in Fluids

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???The definitive version is available at www3.interscience.wiley.com '. Copyright John Wiley and Sons Ltd. DOI: 10.1002/fld.340 [Full text of this article is not available in the UHRA]There are many practical situations when jets are emanating from non-axis-symmetric apertures, yet numerical simulations of such three-dimensional jets are scarce and most of them have failed to reproduce some of the unique flow features. Examples of this type of jets are gas leaks from flanges. These can be treated as jets issuing from high aspect ratio rectangular orifices. The present work consists of a series of large eddy simulations typifying such jets using different inflow boundary conditions. Good agreement with available experiments was observed provided appropriate boundary conditions were present. A discrete method for formulating turbulence data with a known energy spectrum for an inflow condition is outlined and evaluated with three other inflow conditions???a steady uniform profile, a steady parabolic profile and pseudo-random noise. The implementation of the new inlet condition results in a more realistic centreline velocity decay where the division between the end of the potential core region and the start of the characteristic decay region is clearly visible. Large velocity oscillations are also observed in the final quarter of the domain (15???20 slot widths downstream). Similar oscillations have been observed in real jets. Off-centre mean velocity peaks are present along the major axis 10 slot widths downstream of the exit in all the simulations. The peaks are approximately 3% of the centreline velocity. The presence of the off-centre peaks are proved to be independent of jet inflow boundary conditions and an explanation for the mechanism causing the off-centre peaks is given

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“…Computational fluid dynamics (CFD) models have been applied widely to a number of natural settings using both 2‐dimensional (Jackson and Hunt, ; Castro, ; Byrne and Holdo, ; Abe et al , ; Nicholas, ; Safarzadeh et al , ) and more recently 3‐dimensional numerical simulations (Lane et al , ; Nguyen and Nestmann, ; Inkratas, et al , ; Shi and Huang, ). In particular the 3‐D modelling approach can provide detailed patterns of flow behaviour over non‐uniform topography (Lee et al ; Lun et al , ; Stangroom, ), enabling a more thorough examination of complex environments such as natural dune forms and their associated airflow fields.…”

Section: Introductionmentioning

confidence: 99%

Investigation of three‐dimensional wind flow behaviour over coastal dune morphology under offshore winds using computational fluid dynamics (CFD) and ultrasonic anemometry

Jackson

Beyers

Lynch

et al. 2011

Earth Surf Processes Landf

104

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Effects of increased geometric complexity on the comparison between computational and experimental simulations

Cited by 11 publications

References 2 publications

Numerical simulations of pollutant dispersion in an idealized urban area, for different meteorological conditions

Numerical simulations of pollutant dispersion in an idealized urban area, for different meteorological conditions

Simulations of high‐aspect‐ratio jets

Investigation of three‐dimensional wind flow behaviour over coastal dune morphology under offshore winds using computational fluid dynamics (CFD) and ultrasonic anemometry

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