Statistics of the turbulent/non-turbulent interface in a spatially developing mixing layer
Type
ArticleKAUST Department
Clean Combustion Research CenterMechanical Engineering Program
Physical Science and Engineering (PSE) Division
Reactive Flow Modeling Laboratory (RFML)
Date
2014-06-02Online Publication Date
2014-06-02Print Publication Date
2014-09-02Permanent link to this record
http://hdl.handle.net/10754/563585
Metadata
Show full item recordAbstract
The thin interface separating the inner turbulent region from the outer irrotational fluid is analysed in a direct numerical simulation of a spatially developing turbulent mixing layer. A vorticity threshold is defined to detect the interface separating the turbulent from the non-turbulent regions of the flow, and to calculate statistics conditioned on the distance from this interface. The conditional statistics for velocity are in remarkable agreement with the results for other free shear flows available in the literature, such as turbulent jets and wakes. In addition, an analysis of the passive scalar field in the vicinity of the interface is presented. It is shown that the scalar has a jump at the interface, even stronger than that observed for velocity. The strong jump for the scalar has been observed before in the case of high Schmidt number (Sc). In the present study, such a strong jump is observed for a scalar with Sc ≈ 1. Conditional statistics of kinetic energy and scalar dissipation are presented. While the kinetic energy dissipation has its maximum far from the interface, the scalar dissipation is characterised by a strong peak very close to the interface. Finally, it is shown that the geometric features of the interfaces correlate with relatively large scale structures as visualised by low-pressure isosurfaces. © 2014 Taylor & Francis.Publisher
Informa UK LimitedJournal
Journal of Turbulenceae974a485f413a2113503eed53cd6c53
10.1080/14685248.2014.919394