CaltechAUTHORS
  A Caltech Library Service

Small-Scale Dissipation in Supercritical, Transitional Mixing Layers

Okong'o, N. A. and Bellan, J. (2009) Small-Scale Dissipation in Supercritical, Transitional Mixing Layers. In: 47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition. American Institute of Aeronautics and Astronautics , Reston, VA, Art. No. 2009-807. ISBN 978-1-60086-973-0. https://resolver.caltech.edu/CaltechAUTHORS:20200117-100544207

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20200117-100544207

Abstract

The dissipation and small-scale dissipation is calculated for transitional states obtained elsewhere from Direct Numerical Simulations (DNS) of temporal, supercritical mixing layers for two species systems, O₂/H₂ and C₇H₁₆/N₂, so as to understand their species-independent and species-dependent aspects. The effect of filter size on the results was also investigated, with filtering exclusively performed in the dissipation regime of the energy spectrum. Both domain-average dissipation and the small-scale dissipation were analyzed in terms of the three mode contributions to them due to the viscous, heat and species-mass fluxes. The species-mass flux originated contribution dominates both the dissipation and the small-scale dissipation for all simulations and its percentage of the total dissipation or of the small-scale dissipation varies in a very small range across the species system, the initial Reynolds number and the perturbation wavelength used to excite the layer. For a filter size that is four times the DNS grid size, the proportion of each small-scale dissipation mode in the total small-scale dissipation is similar to that obtained at the DNS scale, indicating a scale similarity. It was also found that the percentage of total small-scale dissipation in the total DNS dissipation is only species-system and filter size dependent but nearly independent of the initial conditions. With filter size increase, the increase in the small-scale dissipation portion of the DNS dissipation has similar functional variation for both species systems, although the fraction reached by C₇H₁₆/N₂ layers is much larger than for O₂/H₂ ones. Normalization by the results obtained at the smallest filter size led to highlighting several aspects that are only species-system dependent with increasing the filter size. Backscatter was shown to occur over a substantial percentage of the computational domain, and its magnitude was found to be a substantial fraction of the positive small-scale dissipation. A four fold increase in filter size decreased the spatial extent of backscatter by only at most 32%, 13% and 7.5% for the viscous, heat and species-mass flux originated modes. The implications or these results for Larger Eddy Simulation modeling are discussed.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.2514/6.2009-807DOIArticle
ORCID:
AuthorORCID
Bellan, J.0000-0001-9218-7017
Additional Information:© 2009 by California Institute of Technology. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Published online: 15 Jun 2012.
Other Numbering System:
Other Numbering System NameOther Numbering System ID
AIAA Paper2009-807
Record Number:CaltechAUTHORS:20200117-100544207
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200117-100544207
Official Citation:Small-Scale Dissipation in Supercritical, Transitional Mixing Layers. Josette Bellan and Nora Okong'o. 47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition. January 2009; doi: 10.2514/6.2009-807
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100787
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Jan 2020 18:51
Last Modified:17 Jan 2020 18:51

Repository Staff Only: item control page