Original title: Annular impinging jets and an active control of hysteretic effects
Authors: Devani, Yogendrasasidhar ; Antošová, Zuzana ; Trávníček, Zdeněk
Document type: Research reports
Year: 2022
Language: eng
Abstract: An annular air jet with and without flow control was studied experimentally using flow visualization and measurements of the wall pressure and flow velocity by the Pitot and Prandtl probes and the hot-wire anemometer. To investigate flow control swirling effects, eight synthetic jets were generated from the annular nozzle center body.The experiments cover Reynolds numbers 4000–10000 (evaluated from the outer exit diameter of the annular nozzle). For Re<9000, the bistability and hysteresis were identified and two different flow field patterns (A and B) were found under the same boundary conditions. For A pattern, a small recirculation area (bubble) of separated flow is attached to the nozzle center body. For B pattern, a large recirculation area of separated flow bridges entire nozzle-to-wall distance. For higher Re > 9000, the bistability and hysteresis were not found.Flow control swirling effects causes suppression of the hysteresis. Moreover, weak flow control causes that the entire annular jet is forced into a precessing motion.
Keywords: annular jet; bistability; hysteresis; impinging jet
Project no.: GC21-26232J (CEP)
Funding provider: GA ČR

Institution: Institute of Thermomechanics AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: https://hdl.handle.net/11104/0336270

Permalink: http://www.nusl.cz/ntk/nusl-511836


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Research > Institutes ASCR > Institute of Thermomechanics
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