An experimental study of a reactive plume in grid turbulence

Brown, Richard J.; Bilger, R.W.

doi:10.1017/s0022112096002054

Cited by 51 publications

(23 citation statements)

References 48 publications

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“…For example, a study of point sources in a fully developed pipe flow at Re = 2650 was performed by Brethouwer et al (1999), who also obtained satisfactory agreement with the experiments of Brown and Bilger (1996) on scalar mixing in grid turbulence. A stochastic model was tested by Iliopoulos and Hanratty (1999) using the data obtained from their DNS study on point source dispersion in fully developed channel flow at Re = 4520.…”

Section: Introductionmentioning

confidence: 81%

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

Boppana

Xie

Castro

2011

Flow Turbulence Combust

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Large-eddy simulations of the dispersion from scalar line sources at various locations within a fully developed turbulent channel flow at Re = uh/ν = 10400 are presented. Both mean and fluctuating scalar quantities are compared with those from the single available set of experimental data (Lavertu and Mydlarski, 2005) and differences are highlighted and discussed. The results are also discussed in the context of scalar dispersion in other kinds of turbulent flows, e.g. homogeneous shear-flow. Initial computations at a much lower Reynolds number are also reported and compared with the two available direct numerical simulation data sets.

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Section: Introductionmentioning

confidence: 81%

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

Boppana

Xie

Castro

2011

Flow Turbulence Combust

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“…The concentration for ozone has been varied in between [7.350x10 11 … 1.225x10 12 ] molcm -3 . The ozone concentration has been chosen to be lower than the one in the experiment of Brown and Bilger (1996) in order to provide a more realistic atmospheric scenario. Table 1.…”

Section: Sensitivity Analysis and Resultsmentioning

confidence: 99%

“…The wind tunnel experiment by Brown and Bilger (1996) is used to provide the first case study for a reacting plume. The nominal mean axial velocity of the flow is U =0.…”

Section: Model Validation and Uncertainties For Brown And Bilger Plumementioning

confidence: 99%

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The effects of parametric uncertainties in simulations of a reactive plume using a Lagrangian stochastic model

Ziehn

Dixon

Tomlin

2009

Atmospheric Environment

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Abstract:A combined Lagrangian stochastic model with micro mixing and chemical sub-models is used to investigate a reactive plume of nitrogen oxides (NO x ) released into a turbulent grid flow doped with ozone (O 3 ). Sensitivities to the model input parameters are explored for high NO x model scenarios. A wind tunnel experiment is used to provide the simulation conditions for the first case study where photolysis reactions are not included and the main uncertainties occur in the parameters defining the turbulence scales, the source size and the reaction rate of NO (nitric oxide) with O 3 . Using nominal values of the parameters from previous studies, the model gives a good representation of the radial profile of the conserved scalar [NO x ] compared to the experiments, although the width of the simulated profile is slightly smaller, especially at longer distances from the source. For this scenario, the Lagrangian velocity structure function coefficient has the largest impact on simulated [NO x ] profiles. At the next stage photolysis reactions are included in a chemical scheme consisting of eight reactions between species NO, O, O 3 and NO 2 . The high dimensional model representation (HMDR) method is used to investigate the effects of uncertainties in the various model inputs resulting from the parameterisation of important physical and chemical processes in the reactive plume model, on the simulation of primary and secondary chemical species concentrations. Both independent and interactive effects of the parameters are studied. In total 22 parameters are assumed to be uncertain, among them the turbulence parameters, temperature dependant rate parameters, photolysis rates, temperature, fraction of NO in total NO x at the source and background concentration of O 3 . Only uncertainties in the mixing time scale coefficient and the structure function coefficient are responsible for the variance in the [NO x ] radial profile. On the other hand, the variance in the [O 3 ] profile is caused by parameters describing both physical and chemical processes.

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“…These theories reference the spreading width of a diffusing material released into homogeneous turbulence, revealing that the relationship between the increasing rate of the spreading width and the diffusion time depends on whether the diffusion time is smaller or larger than the time scale of eddies in the flow. The relationship has been investigated further with time-average scalar statistics including mean concentration, concentration fluctuation intensity and the turbulent diffusion coefficient by experimental and numerical methods [6] [7] [8] [9]. Owing to the progress of research on the diffusion theory, the diffusion prediction has become more accurate and speedy.…”

Section: Introductionmentioning

confidence: 99%

Diffusion Process of High Concentration Spikes in a Quasi-Homogeneous Turbulent Flow

Endo¹,

Shao²,

Tsukahara³

et al. 2016

OJFD

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When a mass spreads in a turbulent flow, areas with obviously high concentration of the mass compared with surrounding areas are formed by organized structures of turbulence. In this study, we extract the high concentration areas and investigate their diffusion process. For this purpose, a combination of Planar Laser Induced Fluorescence (PLIF) and Particle Image Velocimetry (PIV) techniques was employed to obtain simultaneously the two fields of the concentration of injected dye and of the velocity in a water turbulent channel flow. With focusing on a quasi-homogeneous turbulence in the channel central region, a series of PLIF and PIV images were acquired at several different downstream positions. We applied a conditional sampling technique to the PLIF images to extract the high concentration areas, or spikes, and calculated the conditional-averaged statistics of the extracted areas such as length scale, mean concentration, and turbulent diffusion coefficient. We found that the averaged length scale was constant with downstream distance from the diffusion source and was smaller than integral scale of the turbulent eddies. The spanwise distribution of the mean concentration was basically Gaussian, and the spanwise width of the spikes increased linearly with downstream distance from the diffusion source. Moreover, the turbulent diffusion coefficient was found to increase in proportion to the spanwise distance from the source. These results reveal aspects different from those of regular mass diffusion and let us conclude that the diffusion process of the spikes differs from that of regular mass diffusion.

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An experimental study of a reactive plume in grid turbulence

Cited by 51 publications

References 48 publications

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

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

The effects of parametric uncertainties in simulations of a reactive plume using a Lagrangian stochastic model

Diffusion Process of High Concentration Spikes in a Quasi-Homogeneous Turbulent Flow

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