Large-Eddy Simulation of Dispersion from Line Sources in a Turbulent Channel Flow

Boppana, V. B. L.; Xie, Zheng-Tong; Castro, Ian P.

doi:10.1007/s10494-011-9356-x

Cited by 19 publications

(21 citation statements)

References 36 publications

(86 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More recently, Boppana et al. ( 2012 ) studied the relatively simpler case of dispersion from a line source in channel flow at a finite Reynolds number of 10800 and still underlines the difficulty implied in investigating scalar dispersion from small sources by means of LES, and the need of thorough validations.…”

Section: Introductionmentioning

confidence: 99%

On the Convergence and Capability of the Large-Eddy Simulation of Concentration Fluctuations in Passive Plumes for a Neutral Boundary Layer at Infinite Reynolds Number

Ardeshiri

Cassiani

Park

et al. 2020

Boundary-Layer Meteorol

View full text Add to dashboard Cite

Large-eddy simulation (LES) experiments have been performed using the Parallelized LES Model (PALM). A methodology for validating and understanding LES results for plume dispersion and concentration fluctuations in an atmospheric-like flow is presented. A wide range of grid resolutions is shown to be necessary for investigating the convergence of statistical characteristics of velocity and scalar fields. For the scalar, the statistical moments up to the fourth order and the shape of the concentration probability density function (p.d.f.) are examined. The mean concentration is influenced by grid resolution, with the highest resolution simulation showing a lower mean concentration, linked to larger turbulent structures. However, a clear tendency to convergence of the concentration variance is observed at the two higher resolutions. This behaviour is explained by showing that the mechanisms driving the mean and the variance are differently influenced by the grid resolution. The analysis of skewness and kurtosis allows also the obtaining of general results on plume concentration fluctuations. Irrespective of grid resolution, a family of Gamma p.d.f.s well represents the shape of the concentration p.d.f. but only beyond the peak of the concentration fluctuation intensity. In the early plume dispersion phases, the moments of the p.d.f. are in good agreement with those generated by a fluctuating plume model. To the best of our knowledge, our study demonstrates for the first time that, if resolution and averaging time are adequate, atmospheric LES provides a trustworthy representation of the high order moments of the concentration field, up to the fourth order, for a dispersing plume.

show abstract

Section: Introductionmentioning

confidence: 99%

On the Convergence and Capability of the Large-Eddy Simulation of Concentration Fluctuations in Passive Plumes for a Neutral Boundary Layer at Infinite Reynolds Number

Ardeshiri

Cassiani

Park

et al. 2020

Boundary-Layer Meteorol

View full text Add to dashboard Cite

show abstract

“…Stapountzis et al 1986;Lavertu and Mydlarski 2005;Lepore and Mydlarski 2011) and numerical (e.g. Boppana et al 2012) PDFs of passive scalar obtained in turbulent channels. Notably, Venaille and Sommeria (2008) have shown that in confined turbulence the gamma distribution (Eq.…”

Section: Analytical Pdf Modelsmentioning

confidence: 99%

“…Boppana et al. 2012 ) PDFs of passive scalar obtained in turbulent channels. Notably, Venaille and Sommeria ( 2008 ) have shown that in confined turbulence the gamma distribution (Eq.…”

Section: Phenomenologically-based Approachesmentioning

confidence: 99%

Concentration Fluctuations from Localized Atmospheric Releases

Cassiani

Bertagni

Marro

et al. 2020

Boundary-Layer Meteorol

View full text Add to dashboard Cite

We review the efforts made by the scientific community in more than seventy years to elucidate the behaviour of concentration fluctuations arising from localized atmospheric releases of dynamically passive and non-reactive scalars. Concentration fluctuations are relevant in many fields including the evaluation of toxicity, flammability, and odour nuisance. Characterizing concentration fluctuations requires not just the mean concentration but also at least the variance of the concentration in the location of interest. However, for most purposes the characterization of the concentration fluctuations requires knowledge of the concentration probability density function (PDF) in the point of interest and even the time evolution of the concentration. We firstly review the experimental works made both in the field and in the laboratory, and cover both point sources and line sources. Regarding modelling approaches, we cover analytical, semi-analytical, and numerical methods. For clarity of presentation we subdivide the models in two groups, models linked to a transport equation, which usually require a numerical resolution, and models mainly based on phenomenological aspects of dispersion, often providing analytical or semi-analytical relations. The former group includes: large-eddy simulations, Reynolds-averaged Navier–Stokes methods, two-particle Lagrangian stochastic models, PDF transport equation methods, and heuristic Lagrangian single-particle methods. The latter group includes: fluctuating plume models, semi-empirical models for the concentration moments, analytical models for the concentration PDF, and concentration time-series models. We close the review with a brief discussion highlighting possible useful additions to experiments and improvements to models.

show abstract

“…LES, which parametrizes the smallest scales of turbulence, has been successful in simulating dispersion at close and moderate distances from the source (e.g. Boppana et al (2010Boppana et al ( , 2012; Matheou et al (2016); Ardeshiri et al (2020)). DNS, which resolves all details of the flow, is now becoming affordable for atmospheric studies (e.g.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of two common source estimation measurement strategies using large-eddy simulation of plume dispersion under neutral atmospheric conditions

Ražnjević

Heerwaarden

Krol

2022

Preprint

View full text Add to dashboard Cite

Abstract. This study uses large-eddy simulations (LES) to evaluate two widely-used observational techniques that estimate point source emissions. We evaluate the use of car measurements perpendicular to the wind direction and the commonly used Other Tracer Method 33A (OTM33A). The LES study simulates a plume from a point source released into a stationary, homogeneous and neutral atmospheric surface layer over flat terrain. This choice is motivated by our ambition to validate the observational methods under controlled conditions where they are expected to perform well since the sources of uncertainties are minimized. Three plumes with different release heights were sampled in a manner that mimics sampling according to car transects and the stationary OTM33A method. Subsequently, source strength estimates are compared to the true source strength used in the simulation. Standard deviations of the estimated source strengths decay proportionally to the inverse of the square root of the number of averaged transects, showing statistical independence of individual samples. The analysis shows that for the car transect measurements at least 15 repeated measurement series need to be averaged to obtain a source strength within 40 % of the true source strength. For the OTM33A analysis, which recommends measurements within 200 m from the source, the estimates of source strengths have similar values close to the source, which is caused by insufficient dispersion of the plume by turbulent mixing close to the source. Additionally, the derived source strength is substantially overestimated with the OTM33A method. This overestimation is driven by the proposed OTM33A dispersion coefficients, which are too large for this specific case. This suggests that the conditions under which the OTM33A dispersion constants were derived, were likely influenced by motions with length scales beyond the scale of the surface layer. Lastly, our simulations indicate that, due to wind-shear effects, the position of the time-averaged centerline of the plumes may differ from the plume emission height. This mismatch can be an additional source of error if a Gaussian plume model (GPM) is used to interpret the measurement. In case of the car transect measurements, a correct source estimate then requires an adjustment of the source height in the GPM.

show abstract

Large-Eddy Simulation of Dispersion from Line Sources in a Turbulent Channel Flow

Cited by 19 publications

References 36 publications

On the Convergence and Capability of the Large-Eddy Simulation of Concentration Fluctuations in Passive Plumes for a Neutral Boundary Layer at Infinite Reynolds Number

On the Convergence and Capability of the Large-Eddy Simulation of Concentration Fluctuations in Passive Plumes for a Neutral Boundary Layer at Infinite Reynolds Number

Concentration Fluctuations from Localized Atmospheric Releases

Evaluation of two common source estimation measurement strategies using large-eddy simulation of plume dispersion under neutral atmospheric conditions

Contact Info

Product

Resources

About