Targeted turbulent structure control in wall-bounded flows via localized heating
Abstract
A targeted turbulent flow control strategy, based on selective heating of streamwise-aligned heat strips, is assessed for drag reduction using direct numerical simulations of variable viscosity and compressible turbulent channel flows. As increasing the temperature of a gas increases its viscosity, heating is generally an unfavorable drag mitigation approach. However, through a selective spatial arrangement of the heating array, the slight increase in viscosity and decrease in density can serve to modify the organization of the streamwise-aligned structures and the likelihood of the ejection and sweep events near the wall. This can, under specific conditions, lead to a very modest drag reduction. The optimal spatial arrangement is identified using a bidimensional empirical mode decomposition and targets the near-wall, large-scale turbulent motion. The drag coefficient, at constant mass flow rate, remains unchanged with heating despite up to an 11% increase in the local viscosity above the heating strips. When accounting for the viscosity variation in the drag reduction calculation, an effective drag reduction of 6% is observed.
Additional Information
© 2020 Published under license by AIP Publishing. Submitted: 5 January 2020; Accepted: 11 February 2020; Published Online: 3 March 2020. This research was enabled in part by support provided by SciNet (www.scinethpc.ca), Sharcnet (www.sharcnet.ca), and Compute Canada (www.computecanada.ca). The authors would like to acknowledge the support from the Natural Sciences and Engineering Council of Canada (NSERC) through the CGS-M and PGS-D programs.Attached Files
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Additional details
- Eprint ID
- 101689
- Resolver ID
- CaltechAUTHORS:20200303-161104637
- SciNet
- Sharcnet
- Compute Canada
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Created
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2020-03-04Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field