Experimental analysis of dominant instabilities in coaxial jets
2011 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 23, no 2, 024103- p.Article in journal (Refereed) Published
An experimental analysis of the dominant instabilities in the near field of two coaxial jets is presented and discussed. Different inner/outer jet velocity pairs (U-i, U-o) have been tested in order to investigate the effect of both velocity ratio r(u) = U-o/U-i and Reynolds number. Three main instabilities have emerged depending on the velocity ratio. For r(u) < 0.75, the coaxial jets dynamic is driven by the inner shear layer. For r(u) > 1.6, the outer shear layer dominates the near field vortex dynamics while for r(u) nearly unitary, the vortex shedding behind the separating wall imposes its own dynamics. A new scaling relationship is proposed to improve the estimation of the shedding frequency with respect to the one found in literature.
Place, publisher, year, edition, pages
2011. Vol. 23, no 2, 024103- p.
IdentifiersURN: urn:nbn:se:kth:diva-31603DOI: 10.1063/1.3553280ISI: 000287812800023OAI: oai:DiVA.org:kth-31603DiVA: diva2:406297
QC 201103252011-03-252011-03-212011-03-25Bibliographically approved