Conditional dissipation of scalars in homogeneous turbulence: closure for MMC modelling
Article
Article Title | Conditional dissipation of scalars in homogeneous turbulence: closure for MMC modelling |
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ERA Journal ID | 92 |
Article Category | Article |
Authors | |
Author | Wandel, Andrew P. |
Journal Title | Combustion Theory and Modelling |
Journal Citation | 17 (4), pp. 707-748 |
Number of Pages | 42 |
Year | 2013 |
Place of Publication | Abingdon, Oxon. United Kingdom |
ISSN | 1364-7830 |
1741-3559 | |
Digital Object Identifier (DOI) | https://doi.org/10.1080/13647830.2013.794391 |
Abstract | While the mean and unconditional variance are to be predicted well by any reasonable turbulent combustion model, these are generally not sufficient for the accurate modelling of complex phenomena such as extinction/reignition. An additional criterion has been recently introduced: accurate modelling of the dissipation timescales associated with fluctuations of scalars about their conditional mean (conditional dissipation timescales). Analysis of Direct Numerical Simulation (DNS) results for a passive scalar shows that the conditional dissipation timescale is of the order of the integral timescale and smaller than the unconditional dissipation timescale. A model is proposed: the conditional dissipation timescale is proportional to the integral timescale. This model is used in Multiple Mapping Conditioning (MMC) modelling for a passive scalar case and a reactive scalar case, comparing to DNS results for both. The results show that this model improves the accuracy of MMC predictions so as to match the DNS results more closely using a relatively-coarse spatial resolution compared to other turbulent combustion models. |
Keywords | conditional timescale; direct numerical simulations; multiple mapping conditioning; scalar dissipation; turbulent combustion |
ANZSRC Field of Research 2020 | 400402. Chemical and thermal processes in energy and combustion |
401213. Turbulent flows | |
400407. Process control and simulation | |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Computational Engineering and Science Research Centre |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q2016/conditional-dissipation-of-scalars-in-homogeneous-turbulence-closure-for-mmc-modelling
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