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Scaling of the turbulent/non-turbulent interface in boundary layers
| Content Provider | Scilit |
|---|---|
| Author | Chauhan, Kapil Philip, Jimmy Marusic, Ivan |
| Copyright Year | 2014 |
| Description | Scaling of the interface that demarcates a turbulent boundary layer from the non-turbulent free stream is sought using theoretical reasoning and experimental evidence in a zero-pressure-gradient boundary layer. The data-analysis, utilising particle image velocimetry (PIV) measurements at four different Reynolds numbers ( $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\delta u_{\tau }/\nu =1200\mbox{--}14\, 500$ ), indicates the presence of a viscosity dominated interface at all Reynolds numbers. It is found that the mean normal velocity across the interface and the tangential velocity jump scale with the skin-friction velocity $u_{\tau }$ and are approximately $u_{\tau }/10$ and $u_{\tau }$ , respectively. The width of the superlayer is characterised by the local vorticity thickness $\delta _{\omega }$ and scales with the viscous length scale $\nu /u_{\tau }$ . An order of magnitude analysis of the tangential momentum balance within the superlayer suggests that the turbulent motions also scale with inner velocity and length scales $u_{\tau }$ and $\nu /u_{\tau }$ , respectively. The influence of the wall on the dynamics in the superlayer is considered via Townsend’s similarity hypothesis, which can be extended to account for the viscous influence at the turbulent/non-turbulent interface. Similar to a turbulent far-wake the turbulent motions in the superlayer are of the same order as the mean velocity deficit, which lends to a physical explanation for the emergence of the wake profile in the outer part of the boundary layer. |
| Related Links | http://minerva-access.unimelb.edu.au/bitstream/11343/214558/1/Interface_Re_Scaling_R2.pdf https://www.cambridge.org/core/services/aop-cambridge-core/content/view/A5B06B97B07DF59C89ABCCEB9608576E/S0022112014002985a.pdf/div-class-title-scaling-of-the-turbulent-non-turbulent-interface-in-boundary-layers-div.pdf |
| Ending Page | 328 |
| Page Count | 31 |
| Starting Page | 298 |
| ISSN | 00221120 |
| e-ISSN | 14697645 |
| DOI | 10.1017/jfm.2014.298 |
| Journal | Journal of Fluid Mechanics |
| Volume Number | 751 |
| Language | English |
| Publisher | Cambridge University Press (CUP) |
| Publisher Date | 2014-07-25 |
| Access Restriction | Open |
| Subject Keyword | Journal of Fluid Mechanics Fluids and Plasmas Physics layer Structure Boundary Layers Turbulent Boundary Layers Turbulent Flows |
| Content Type | Text |
| Resource Type | Article |
| Subject | Applied Mathematics Mechanics of Materials Condensed Matter Physics Mechanical Engineering |
