The role of vortex shedding in the mixing of coaxial jets

Authors: Segalini, A. S., Talamelli, A.
Document Type: Conference
Pubstate: Published
Journal: Proc. 19th AIDAA 2007
Year: 2007


In the present work an experimental study of the mixing in a coaxial jet configuration without tangential velocity has been done. The work presents an experimental comparison between two different configurations characterized by different separation walls. The analysis is aimed at verifying if the onset of an absolute instability, caused by the presence of the wake behind the separation wall, is able to affect the mixing between the two coaxial streams. Velocity and temperature measurements, where the temperature was used as a passive scalar, have been performed by means of hot-wire anemometry up to 12 diameters from the nozzle exit. Measurement results fully characterize the mean velocity and temperature distribution in the flow. Mixing thicknesses are finally used as indicators of the mixing process showing that the presence of a thick separation wall increases the mixing between the two streams making the process faster and more efficient.