Experimental study of oscillating-grid turbulence interacting with a solid boundary
| Autor: | Mark W. McCorquodale, Richard J. Munro |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Physics
Turbulence Mechanical Engineering Boundary (topology) Energy flux Flux Vertical plane Mechanics Reynolds stress Condensed Matter Physics 01 natural sciences 010305 fluids & plasmas Physics::Fluid Dynamics Classical mechanics Mechanics of Materials 0103 physical sciences Turbulence kinetic energy 010306 general physics Convection–diffusion equation |
| Zdroj: | Journal of Fluid Mechanics. 813:768-798 |
| ISSN: | 1469-7645 0022-1120 |
| DOI: | 10.1017/jfm.2016.843 |
| Popis: | The interaction between oscillating-grid turbulence and a solid, impermeable boundary (positioned below, and aligned parallel to, the grid) is studied experimentally. Instantaneous velocity measurements, obtained using two-dimensional particle imaging velocimetry in the vertical plane through the centre of the (horizontal) grid, are used to study the effect of the boundary on the root-mean-square velocity components, the vertical flux of turbulent kinetic energy (TKE) and the terms in the Reynolds stress transport equation. Identified as a critical aspect of the interaction is the blocking of a vertical flux of TKE across the boundary-affected region. Terms of the Reynolds stress transport equations show that the blocking of this energy flux acts to increase the boundary-tangential turbulent velocity component, relative to the far-field trend, but not the boundary-normal velocity component. The results are compared with previous studies of the interaction between zero-mean-shear turbulence and a solid boundary. In particular, the data reported here are in support of viscous and ‘return-to-isotropy’ mechanisms governing the intercomponent energy transfer previously proposed, respectively, by Perot & Moin (J. Fluid Mech., vol. 295, 1995, pp. 199–227) and Walkeret al.(J. Fluid Mech., vol. 320, 1996, pp. 19–51), although we note that these mechanisms are not independent of the blocking of energy flux and draw parallels to the related model proposed by Magnaudet (J. Fluid Mech., vol. 484, 2003, pp. 167–196). |
| Databáze: | OpenAIRE |
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