A novel forcing technique to simulate turbulent mixing in a decaying scalar field
Abstract
To realize the full potential of Direct Numerical Simulation in turbulent mixing studies, it is necessary to develop numerical schemes capable of sustaining the flow physics of turbulent scalar quantities. In this work, a new scalar field forcing technique, termed "linear scalar forcing," is presented and evaluated for passive scalars. It is compared to both the well-known mean scalar gradient forcing technique and a low waveshell spectral forcing technique. The proposed forcing is designed to capture the physics of one-time scalar variance injection and the subsequent self-similar turbulent scalar field decay, whereas the mean scalar gradient forcing and low waveshell forcing techniques are representative of continuous scalar variance injection. The linear scalar forcing technique is examined over a range of Schmidt numbers, and the behavior of the proposed scalar forcing is analyzed using single and two-point statistics. The proposed scalar forcing technique is found to be perfectly isotropic, preserving accepted scalar field statistics (fluxes) and distributions (scalar quantity, dissipation rate). Additionally, it is found that the spectra resulting from the three scalar forcing techniques are comparable for unity Schmidt number conditions, but differences manifest at high Schmidt numbers. These disparities are reminiscent of those reported between scaling arguments suggested by theoretical predictions and experimental results for the viscous-convective subrange.
Additional Information
(Received 12 February 2013; accepted 16 August 2013; published online 6 September 2013). © 2013 AIP Publishing LLC. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant No. OCI-1053575. This research was supported by the National Science Foundation CAREER award Grant No. 1056142. Also, the authors would like to acknowledge Adam Cheminet (ONERA), whose contribution was integral in the early stages of this study.Attached Files
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Additional details
- Eprint ID
- 41697
- Resolver ID
- CaltechAUTHORS:20131005-183833026
- OCI-1053575
- NSF
- 1056142
- National Science Foundation CAREER award
- Created
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2013-10-07Created from EPrint's datestamp field
- Updated
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2023-10-25Created from EPrint's last_modified field