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Microbubbly drag reduction in Taylor–Couette flow in the wavy vortex regime
| Content Provider | Scilit |
|---|---|
| Author | Sugiyama, Kazuyasu Calzavarini, Enrico Lohse, Detlef |
| Copyright Year | 2008 |
| Description | We investigate the effect of microbubbles on Taylor–Couette flow by means of direct numerical simulations. We employ an Eulerian–Lagrangian approach with a gas–fluid coupling based on the point-force approximation. Added mass, drag, lift and gravity are taken into account in the modelling of the motion of the individual bubble. We find that very dilute suspensions of small non-deformable bubbles (volume void fraction below 1%, zero Weber number and bubble Reynolds number ≲10) induce a robust statistically steady drag reduction (up to 20%) in the wavy vortex flow regime (Re=600–2500). The Reynolds number dependence of the normalized torque (the so-called torque reduction ratio (TRR) which corresponds to the drag reduction) is consistent with a recent series of experimental measurements performed by Murai et al. (J. Phys. Conf. Ser. vol. 14, 2005, p. 143). Our analysis suggests that the physical mechanism for the torque reduction in this regime is due to the local axial forcing, induced by rising bubbles, that is able to break the highly dissipative Taylor wavy vortices in the system. We finally show that the lift force acting on the bubble is crucial in this process. When it is neglected, the bubbles preferentially accumulate near the inner cylinder and the bulk flow is less efficiently modified. Movies are available with the online version of the paper. |
| Related Links | http://arxiv.org/pdf/physics/0703100 https://core.ac.uk/reader/44173839 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/9A900CA4DE7B3CD1C70A98F4404CA151/S0022112008001183a.pdf/div-class-title-microbubbly-drag-reduction-in-taylor-couette-flow-in-the-wavy-vortex-regime-div.pdf |
| Ending Page | 41 |
| Page Count | 21 |
| Starting Page | 21 |
| ISSN | 00221120 |
| e-ISSN | 14697645 |
| DOI | 10.1017/s0022112008001183 |
| Journal | Journal of Fluid Mechanics |
| Volume Number | 608 |
| Language | English |
| Publisher | Cambridge University Press (CUP) |
| Publisher Date | 2008-08-10 |
| Access Restriction | Open |
| Subject Keyword | Journal of Fluid Mechanics Fluids and Plasmas Physics liquid Flow Drag Reduction couette Flow |
| Content Type | Text |
| Resource Type | Article |
| Subject | Applied Mathematics Mechanics of Materials Condensed Matter Physics Mechanical Engineering |
