The moments of the PDF of concentration for gas clouds in the presence of fences

Chatwin, P. C. and Robinson, C. (1997) The moments of the PDF of concentration for gas clouds in the presence of fences. Il nuovo cimento C, 20 C (3). pp. 361-384. ISSN 1826-9885


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A team led by D. J. Hall has conducted many trials, each involving the instantaneous release of a heavy or neutrally buoyant gas in the presence of a fence aligned transverse to the mean flow, thus complementing earlier trials without fences. For each fence and for each Richardson Number Ri, at least 50 repetitions of each release were performed. This allowed estimates to be made of some statistical properties (mean concentration m, standard deviation s, skewness S, kurtosis K), and their variation with time. Typical results are presented and discussed. The strongest influence of the fences on the evolution of m and s with time is vertical mixing, but there are also interesting changes with fence height and type, and with Ri. The possibility of a relationship between m and s is discussed. However, the most remarkable result is, perhaps, that the estimates of S and K are such that, in all cases, the (K, S) plot collapses onto a quadratic curve; this extends the same finding earlier by Mole and Clarke for steady releases and, in particular, suggests strongly that the PDF of concentration is, in practice, determined by only three properties,

Item Type: Article
Additional Information: Paper presented at EUROMECH Colloquium 338 “Atmospheric Turbulence and Dispersion in Complex Terrain” and ERCOFTAC Workshop “Data on Turbulence and Dispersion in Complex Atmospheric Flows”, Bologna, 4-7 September 1995.
Uncontrolled Keywords: Convection, turbulence, and diffusion; air qulity and air pollution; conference proceedings
Subjects: 300 Scienze sociali > 360 Problemi e servizi sociali; associazioni > 363 Altri problemi e servizi sociali > 363.7 Problemi ambientali (classificare qui la tutela ambientale; l’effetto dei rifiuti, dell’inquinamento, delle iniziative per controllarli) > 363.73 Inquinamento > 363.739 Inquinamento di specifici ambienti > 363.7392 Inquinamento atmosferico
500 Scienze naturali e Matematica > 530 Fisica
Depositing User: Marina Spanti
Date Deposited: 11 May 2017 09:04
Last Modified: 11 May 2017 09:04

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