Peculiarities Research of the Turbulence in a Swirling Flow by the LDA Method
RUSSIAN ACADEMY OF SCIENCES NOVOSIBIRSKINST OF THERMOPHYSICS
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The vortex axis precession may have a sufficient influence on the measured values of the swirling flow turbulence characteristics. It was shown that up to 80 of the measured value of the velocity fluctuation in a vortex chamber nay be conditioned by the precession. A quasi-periodic low-frequency movement of the flow kernel is observed in different kinds of swirling flows. This may be the precession of the recirculation region in a flow with a strong swirl. For example in a vortex combustion chamber, the swirling movement spiral occurs. The quasi-periodical oscillation in vortex chamber were observed in our previous investigation. It was shown that the mean flow field was not axi-symmetrical the lines of equal velocity values had the elliptical form. For turbulence measurement in swirling flow it is necessary to evaluate the contribution from quasi-periodical alteration of these parameters since this may overestimate the measured velocity fluctuation. A similar problem appears during the measurement of turbulence in a boundary layer subjected to oscillation in the main flow.
- Fluid Mechanics