Absolute and convective instabilities of a swirling jet-wake shear layerReport as inadecuate




Absolute and convective instabilities of a swirling jet-wake shear layer - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 LadHyX - Laboratoire d-hydrodynamique

Abstract : The absolute AI-convective CI nature of the instability is determined in the family of swirling jet-wake shear layers considered by Martin and Meiburg Phys. Fluids 6, 424 1994 and Lim and Redekopp Eur. J. Mech. B-Fluids 17, 165 1998. This idealized model includes as essential ingredients both the centrifugal instability associated with the swirl difference and the Kelvin-Helmholtz instability associated with the swirl and axial velocity differences between the core and the outer flow. Centrifugally stabilizing or destabilizing swirl differences are found to promote AI, but a centrifugally destabilizing configuration is more effective in triggering such a transition. For sufficiently large swirl differences, both co-flowing jets and wakes may become AI. In the case of jets, a centrifugally destabilizing swirl difference first brings about AI via the axisymmetric mode m=0 in a large range of mean swirl values. By contrast, a centrifugally stabilizing swirl difference triggers AI via the helical mode m=-8. In the case of wakes, a centrifugally destabilizing swirl difference leads to AI via the bending mode m-1 whereas a centrifugally stabilizing swirl difference triggers AI via various negative helical modes m=-1,-2, etc. © 2000 American Institute of Physics.





Author: Thomas Loiseleux - Ivan Delbende - Patrick Huerre -

Source: https://hal.archives-ouvertes.fr/



DOWNLOAD PDF




Related documents