Assessment of the vortex method for Large Eddy Simulation inlet conditions

Mathey, Fabrice; Čokljat, Davor; Bertoglio, Jean-Pierre; Sergent, Emmanuel

doi:10.1504/pcfd.2006.009483

Cited by 217 publications

(78 citation statements)

References 10 publications

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“…The inlet and outlet planes are perpendicular to the flow direction, as required by the vortex method (Mathey et al, 2006) used to generate a time-dependent velocity profile at the inlet (more details in section 4.4). The streamwise, spanwise and vertical coordinates are denoted by x, y and z, respectively.…”

Section: Domainmentioning

confidence: 99%

“…To generate a time-dependent velocity profile with LES, the vortex method is used (Mathey et al, 2006). In the inlet plane, a given number N of vortices are generated and convected randomly at each time step.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…The fluctuations around the prescribed mean streamwise velocity are deduced from the perturbation caused by the vortices in the inlet plane. More details about this technique and validation studies can be found in Mathey et al (2006). Previous studies on air flow around a wall-mounted cube (not presented here) have shown that the flow field can be simulated in an accurate way with N = 190; this value has therefore been retained for the present LES computations.…”

Section: Boundary Conditionsmentioning

confidence: 99%

See 2 more Smart Citations

CFD simulation of near-field pollutant dispersion on a high-resolution grid: A case study by LES and RANS for a building group in downtown Montreal

Gousseau¹,

Blocken²,

Stathopoulos³

et al. 2011

Atmospheric Environment

326

148

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Turbulence modeling and validation by experiments are key issues in the simulation of micro-scale atmospheric dispersion. This study evaluates the performance of two different modeling approaches (RANS standard k-ε and LES) applied to pollutant dispersion in an actual urban environment: downtown Montreal. The focus of the study is on near-field dispersion, i.e. both on the prediction of pollutant concentrations in the surrounding streets (for pedestrian outdoor air quality) and on building surfaces (for ventilation system inlets and indoor air quality). The high-resolution CFD simulations are performed for neutral atmospheric conditions and are validated by detailed wind-tunnel experiments. A suitable resolution of the computational grid is determined by grid-sensitivity analysis. It is shown that the performance of the standard k-ε model strongly depends on the turbulent Schmidt number, whose optimum value is case-dependent and a priori unknown. In contrast, LES with the dynamic subgrid-scale model shows a better performance without requiring any parameter input to solve the dispersion equation.

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Section: Domainmentioning

confidence: 99%

Section: Boundary Conditionsmentioning

confidence: 99%

Section: Boundary Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

CFD simulation of near-field pollutant dispersion on a high-resolution grid: A case study by LES and RANS for a building group in downtown Montreal

Gousseau¹,

Blocken²,

Stathopoulos³

et al. 2011

Atmospheric Environment

326

148

View full text Add to dashboard Cite

show abstract

“…This control of the RANS/LES switch can be achieved either by blending between turbulence and subgrid models [11,12]; or by a unified model, where only one turbulence model is used and its contribution has to be damped to mimic a subgrid closure [8,13,14,15]. Note, for completeness we mention the zonal method [16,17] which employs two distinct regions, one LES and one RANS. The interface between the two zones is prescribed by the user and turbulent fluctuations must be generated as a boundary condition for the LES.…”

Section: /5mentioning

confidence: 99%

Reynolds Stress Structures in the Hybrid RANS/LES of a Planar Channel

Weatheritt

Sandberg

Lozano-Durán

2016

J. Phys.: Conf. Ser.

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“…The same wind conditions are defined at the inlet of both simulations. The turbulence kinetic energy imposed at the inlet of the RANS-based simulation is reproduced in LES by imposing a time-dependent wind-speed profile using the vortex method [34] in FLUENT 14.5. 190 vortices are used in the vortex method because it has provided good results in previous studies on the wind behavior around a wall-mounted cube [35].…”

Section: 1) Uncertainties Associated With Rans-based Simulation In mentioning

confidence: 99%

A model-based data-interpretation framework for improving wind predictions around buildings

Vernay

Raphael

Smith

2015

Journal of Wind Engineering and Industrial Aerodynamics

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Abstract:Although Computational Fluid Dynamics (CFD) simulations are often used to assess wind conditions around buildings, the accuracy of such simulations is often unknown. This paper proposes a datainterpretation framework that uses multiple simulations in combination with measurement data to improve the accuracy of wind predictions. Multiple simulations are generated through varying sets of parameter values. Sets of parameter values are falsified and thus not used for predictions if differences between measurement data and simulation predictions, for any measurement location, are larger than an estimate of uncertainty bounds. The bounds are defined by combining measurement and modelling uncertainties at sensor locations. The framework accounts for time-dependent and spatially-distributed modelling uncertainties that are present in CFD simulations of wind. The framework is applied to the case study of the CREATE Tower located at the National University of Singapore. Values for timedependent inlet conditions, as well as values for the roughness of surrounding buildings, are identified with measurements carried out around the CREATE Tower. Results show that, on average, ranges of

show abstract

Assessment of the vortex method for Large Eddy Simulation inlet conditions

Cited by 217 publications

References 10 publications

CFD simulation of near-field pollutant dispersion on a high-resolution grid: A case study by LES and RANS for a building group in downtown Montreal

CFD simulation of near-field pollutant dispersion on a high-resolution grid: A case study by LES and RANS for a building group in downtown Montreal

Reynolds Stress Structures in the Hybrid RANS/LES of a Planar Channel

A model-based data-interpretation framework for improving wind predictions around buildings

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