ANALYSIS OF FLUTTER CONTROL POSSIBILITY BY COHERENT FORMATIONS IN VORTEX CHAMBERS FLOWS
DOI:
https://doi.org/10.20535/2305-9001.2014.71.35912Keywords:
vortex chamber, flutter, control, coherent vortical structure, statistical characteristics, vortex generator, “reverse vortices decay”Abstract
Purpose.The investigation is devoted to the quest for new effective means of control by coherent vortical structures for improvement of mass and momentum transfer processes in the vortex chambers.
Design/methodology/approach. Non-standard method of selective control by current characteristics is based on the admission to inlet flow the vortical disturbances from wing-shaped fluttering element in intake nozzle of chamber. Using complex technique of experimental research combined visualization of flow, measurements by hot-wire anemometer and special methodology of statistic processing of data. This technique allowed to define and to describe correctly space-time flow fields. The response of the most powerful coherent vortical structure on control actions was studied by means of comparison of current statistic characteristics, amplitude-frequency spectra of actual velocity root-mean-square deviations and space-time distribution of fluctuating velocity energy under conditions of existence or absence of external vortex disturbing influences.
Findings. It is proved that employment of the vortex generator carries out to redistribution of velocity fluctuations energy between different points along the chosen coherent vortical structure region and between the most powerful frequency bands of vortex zone. The “reverse vortices decay” y was found inside some of the typical frequency bands. This phenomenon is related to “negative turbulent viscosity” and creature intensifies transfer processes in the working medium.
Originality/value. Design simplicity of fluttering vortex generator, the possibility of microlevel control and little energy consumption allow to consider suggested method of control as perspective
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