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Article
Main instabilities of coaxial jets
Authors: |
Segalini, A. S., Talamelli, A. |
Document Type: |
Article |
Pubstate: |
Published |
Journal: |
Proc. iTi Conference on Turbulence IV, Bertinoro, Italy, 2010 |
Volume: |
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Year: |
2010 |
AbstractAn experimental analysis of the dominant instabilities in the initial merg- ing region of two coaxial jets is presented. Different inner/outer jet velocity pairs (Ui,Uo) have been tested in order to investigate the effect of both velocity ratio ru = Uo/Ui and Reynolds number in the instability characteristics. Three main in- stabilities have emerged depending on the velocity ratio. For ru < 0.75 the coaxial jets dynamic is driven by the inner shear layer. For ru > 1.6 the outer shear layer dominates the near field vortex dynamics, while for velocity ratios nearly unitary the vortex shedding behind the separating wall imposes its own dynamics.
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