A MIXING MODEL FOR JOINT SCALAR STATISTICS

Citation
K. Sardi et al., A MIXING MODEL FOR JOINT SCALAR STATISTICS, Combustion science and technology, 136(1-6), 1998, pp. 95-123
Citations number
59
Categorie Soggetti
Thermodynamics,"Energy & Fuels","Engineering, Chemical",Engineering
ISSN journal
00102202
Volume
136
Issue
1-6
Year of publication
1998
Pages
95 - 123
Database
ISI
SICI code
0010-2202(1998)136:1-6<95:AMMFJS>2.0.ZU;2-0
Abstract
A stochastic model is proposed to describe the correlation between the scalar fluctuations and their dissipation and the distribution of the conditional scalar dissipation in flows characterised by 'young' scal ar turbulence, such as the mixing layer formed between opposed jets. I t predicts the scalar field from an ensemble of instantaneous scalar i nterfaces of specified functional form, referred to as mixinglets, ran domly displaced in space, and is shown to compare favourably with expe rimental data from counterflows and direct numerical simulations of sc alar fields characterised by short residence times. The model is initi ally formulated to account for molecular diffusion and turbulent conve ction and then extended to include all turbulent transport processes b y incorporating a description for the instantaneous turbulent strain r ates. The contribution of each mechanism to the evolution of the singl e and joint statistics is quantified individually and the ability of t he model to represent conditional scalar statistics with application t o combustion modelling is addressed.