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A numerical study of turbulent line puffs via the renormalization group (RNG) k –ϵ model
Author(s) -
Lee J. H. W.,
Chen G. Q.
Publication year - 1998
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/(sici)1097-0363(19980130)26:2<217::aid-fld637>3.0.co;2-g
Subject(s) - turbulence , physics , vortex , dimensionless quantity , renormalization group , scalar (mathematics) , mechanics , momentum (technical analysis) , mixing (physics) , wake , flow (mathematics) , classical mechanics , geometry , mathematics , mathematical physics , finance , quantum mechanics , economics
The time evolution of a line puff, a turbulent non‐buoyant element with significant momentum, is studied using the renormalization group (RNG) k –ϵ model. The numerical results show that the puff motion is characterized by a vortex pair flow; the computed flow details and scalar mixing characteristics can be described by self‐similar relations beyond a dimensionless time of around 30. The added mass coefficient of the puff motion is found to be approximately unity. The predicted puff flow and mixing rate are substantially similar to those obtained from the standard k –ϵ model and are well supported by experimental data. The computed scalar field reveals significant secondary concentration peaks trailing behind in the wake of the puff. The present results suggest that the overall mixing rate of a puff is primarily determined by the large‐scale motion and that streamline curvature probably plays a minor role. © 1998 John Wiley & Sons, Ltd.