The effect of a circular cylinder on the diffusion of matter by a plume

Tsunoda, Hiroyuki; Sakai, Yasuhiko; Nakamura, Ikuo; Liu, S.

doi:10.1017/s0022112093000205

Cited by 9 publications

(2 citation statements)

References 16 publications

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“…In the case of scalar dispersion from localized sources located near bluff bodies, it is also well established that the decay rate of scalar concentration and the plume spread are considerably affected by the onset of plume meandering. 3,4 From the modeling perspective of the RANS equations, most of the effort has been dedicated to the prediction of the flow field and to the modeling of the Reynolds stress tensor. 5,6,7 Nonetheless, numerical experiments based on Direct Numerical Simulations (DNS) show some differences between the dynamics of the velocity and scalar fields when coherent large-scale structures develop downstream of a bluff body, 8 suggesting the need for extending the analysis to the modeling of the scalar field.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of scalar mixing in the turbulent wake of a square cylinder

Lodato

Rossi

2013

43rd Fluid Dynamics Conference

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Numerical experiments by Large-Eddy Simulation (LES) are performed on the turbulent flow and mixing of a passive scalar past a square cylinder. A Reynolds number of 21 400 is selected, matching available flow measurements from laser-doppler velocimetry (LDV), and the scalar released from a point source downstream of the cylinder. A comparative study of numerical results against LDV data is presented in order to validate the present LES methodology, where sub-grid turbulent stresses are estimated via the WALE similarity mixed model coupled with newly developed constrained filtering operators of arbitrary order and scalar fluxes approximated via the Reynolds analogy. Time-averaged and phaseaveraged statistics for the scalar field, including scalar variance and scalar flux components, are computed to examine further the role of coherent fluctuations associated with largescale structures on the mixing process and to establish a database for turbulence models development and validation.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of scalar mixing in the turbulent wake of a square cylinder

Lodato

Rossi

2013

43rd Fluid Dynamics Conference

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“…Gad-el-Hak & Morton (1979) used a point source of smoke in grid turbulence to measure turbulent fluxes by scattering light from smoke particles to measure relative concentrations and laser-Doppler techniques to measure velocities. More recently Nakamura, Sakai & Miyata (1987) and Tsunoda et al (1993) have made measurements with a spatial resolution close to the Kolmogorov scale using dye solution in grid-generated water turbulence. Britter et al (1983) have studied the effect of stable stratification on turbulent diffusion from a point source in grid turbulence.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of a reactive plume in grid turbulence

Brown

Bilger

1996

J. Fluid Mech.

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Experimental results for a reactive non-buoyant plume of nitric oxide (NO) in a turbulent grid flow doped with ozone (O3) are presented. The Damköhler number (ND) for the experiment is of order unity indicating the turbulence and chemistry have similar timescales and both affect the chemical reaction rate. Continuous measurements of two components of velocity using hot-wire anemometry and the two reactants using chemiluminescent analysers have been made. A spatial resolution for the reactants of four Kolmogorov scales has been possible because of the novel design of the experiment. Measurements at this resolution for a reactive plume are not found in the literature. The experiment has been conducted relatively close to the grid in the region where self-similarity of the plume has not yet developed. Statistics of a conserved scalar, deduced from both reactive and non-reactive scalars by conserved scalar theory, are used to establish the mixing field of the plume, which is found to be consistent with theoretical considerations and with those found by other investigators in non-reactive flows. Where appropriate the reactive species means and higher moments, probability density functions, joint statistics and spectra are compared with their respective frozen, equilibrium and reaction-dominated limits deduced from conserved scalar theory. The theoretical limits bracket reactive scalar statistics where this should be so according to conserved scalar theory. Both reactants approach their equilibrium limits with greater distance downstream. In the region of measurement, the plume reactant behaves as the reactant not in excess and the ambient reactant behaves as the reactant in excess. The reactant covariance lies outside its frozen and equilibrium limits for this value of ND. The reaction rate closure of Toor (1969) is compared with the measured reaction rate. The gradient model is used to obtain turbulent diffusivities from turbulent fluxes. Diffusivity of a non-reactive scalar is found to be close to that measured in non-reactive flows by others.

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References

1995

Concentration Fluctuations and Averaging Time in Vapor Clouds

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The effect of a circular cylinder on the diffusion of matter by a plume

Cited by 9 publications

References 16 publications

Numerical investigation of scalar mixing in the turbulent wake of a square cylinder

Numerical investigation of scalar mixing in the turbulent wake of a square cylinder

An experimental study of a reactive plume in grid turbulence

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