Compressibility effects on large structures in free shear flows

M. Samimy, M. F. Reeder, G. S. Elliott

Research output: Contribution to journalArticlepeer-review


Space-time correlations were used to study compressibility effects on large structures in mixing layers. Two high Reynolds number mixing layers with M c = 0.51 (case 1) and 0.86 (case 2) were studied. The results indicate that the structures in case 1 are similar to those in the incompressible case, but less organized. The structures in case 2 are highly three dimensional, with a good spatial but a poor temporal organization. The streamwise correlations showed a decay rate four to five times greater for case 2 relative to case 1. While the spanwise correlations for case 1 showed trends similar to incompressible mixing layers, the behavior of case 2 was very different. The pressure fluctuations in the fully developed region of case 2 displayed significant rms variation in the spanwise direction with a well-defined pattern. Based on these measurements, the structures in case 2 seem to be of a horseshoe type, transversely spanning the mixing layer with the head in the low-speed side and the legs inclined in both the x-y and the x-z planes.

Original languageEnglish (US)
Pages (from-to)1251-1258
Number of pages8
JournalPhysics of Fluids A
Issue number6
StatePublished - 1992
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)


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