Topical Problems of Fluid Mechanics


Institute of Thermomechanics AS CR, v.v.i.	CTU in Prague Faculty of Mech. Engineering Dept. Tech. Mathematics	MIO Université du Sud Toulon Var - AMU - CNRS - IRD	Czech Pilot centre ERCOFTAC

Annular Impinging Jets and an Active Control of Hysteretic Effects
Devani Y., Antošová Z., Trávníček Z.
Abstract:
An annular impinging air jet with and without flow control was studied experimentally using measurements of the wall pressure and flow velocity by the Pitot probe. To investigate flow control swirling effects, eight synthetic jets were generated from the nozzle center body. The experiments cover Reynolds numbers 4000–10,000 (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, 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 bridges entire nozzle-to-wall distance. For higher Re>9000, the hysteresis were not found.
Keywords:
annular jet, impinging jet, hysteresis

Fulltext: PDF DOI: https://doi.org/10.14311/TPFM.2023.003

In Proceedings Topical Problems of Fluid Mechanics 2023, Prague, 2023, Edited by David Šimurda and Tomáš Bodnár, pp. 13 ISBN 978-80-87012-83-3 (Print) ISSN 2336-5781 (Print)