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DC Field | Value | Language |
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dc.contributor.author | Zhu, Lu | - |
dc.contributor.author | Xi, Li | - |
dc.date.accessioned | 2019-12-02T02:47:45Z | - |
dc.date.available | 2019-12-02T02:47:45Z | - |
dc.date.issued | 2018 | - |
dc.identifier | 10.1088/1742-6596/1001/1/012005 | - |
dc.identifier.citation | Zhu, L., & Xi, L. (2018). Coherent structure dynamics and identification during the multistage transitions of polymeric turbulent channel flow. Journal of Physics: Conference Series, 1001, 012005. | en_US |
dc.identifier.other | 10.1088/1742-6596/1001/1/012005 | - |
dc.identifier.other | 10.1088/1742-6596/1001/1/012005 | - |
dc.identifier.uri | http://hdl.handle.net/11375/25073 | - |
dc.description.abstract | Drag reduction induced by polymer additives in wall-bounded turbulence has been studied for decades. A small dosage of polymer additives can drastically reduce the energy dissipation in turbulent flows and alter the flow structures at the same time. As the polymer-induced fluid elasticity increases, drag reduction goes through several stages of transition with drastically different flow statistics. While much attention in the area of polymer-turbulence interactions has been focused on the onset and the asymptotic stage of maximum drag reduction, the transition between the two intermediate stages – low-extent drag reduction (LDR) and high-extent drag reduction (HDR) – likely reflects a qualitative change in the underlying vortex dynamics according to our recent study [1]. In particular, we proposed that polymers start to suppress the lift-up and bursting of vortices at HDR, leading to the localization of turbulent structures. To test our hypothesis, a statistically robust conditional sampling algorithm, based on Jenong and Hussain [2]'s work, was adopted in this study. The comparison of conditional eddies between the Newtonian and the highly elastic turbulence shows that (i) the lifting "strength" of vortices is suppressed by polymers as reflected by the decreasing lifting angle of the conditional eddy and (ii) the curvature of vortices is also eliminated as the orientation of the head of the conditional eddy changes. In summary, the results of conditional sampling support our hypothesis of polymer-turbulence interactions during the LDR-HDR transition. | en_US |
dc.description.sponsorship | (NSERC) Natural Sciences and Engineering Research Council of Canada: No. RGPIN-2014-04903; (ERC) European Research Council H2020 program (ERC-2014-ADG ‘COTURB’) | en_US |
dc.language.iso | en_US | en_US |
dc.publisher | IOP Publishing | en_US |
dc.subject | Fluid Mechanics | en_US |
dc.subject | Turbulence | en_US |
dc.subject | Vortex Analysis | en_US |
dc.subject | Direct Numerical Simulation | en_US |
dc.subject | Vortex Dynamics | en_US |
dc.subject | Viscoelastic Fluids | en_US |
dc.subject | Drag Reduction | en_US |
dc.subject | Polymer Solution | en_US |
dc.title | Coherent structure dynamics and identification during the multistage transitions of polymeric turbulent channel flow | en_US |
dc.type | Article | en_US |
dc.contributor.department | Chemical Engineering | en_US |
Appears in Collections: | Chemical Engineering Publications |
Files in This Item:
File | Description | Size | Format | |
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ZhuJPhysCS18.pdf | 1.68 MB | Adobe PDF | View/Open |
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