Controlling spatio-temporal evolution of natural and excited square jets via inlet conditions

Artur Tyliszczak*, Bernardus J. Geurts

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The paper presents numerical investigations of square jets in a wide range of Reynolds numbers with varying inlet turbulence characteristics. The research focuses on flow characteristics depending on inflow turbulent length/time scales and excitation frequencies in case of excited jets. It is found that the parameters of inlet turbulence affect the solutions qualitatively when the Reynolds number is sufficiently low. In these cases the impact of varying the turbulent time scale is considerably larger than changing the turbulent length scale. It was also observed that at sufficiently high Reynolds numbers the jets become quite independent of the inlet turbulence characteristics. This confirms findings of Xu et al. (Phys. Fluids, 2013) concerning weak/strong dependence of the jet evolution on inflow conditions. In case of excited jets the excitation frequencies play an important role and influence the jet behaviour most strongly at lower values of the Reynolds number. For some forcing frequencies a bifurcation occurs at sufficiently large forcing amplitudes. This phenomenon turned out to be independent of the assumed length and time scales of the turbulent fluctuations, both in terms of robustness as well as amplitude.

Original languageEnglish
Article number108488
Number of pages15
JournalInternational journal of heat and fluid flow
Volume80
Early online date17 Oct 2019
DOIs
Publication statusPublished - Dec 2019

Keywords

  • Bifurcation phenomenon
  • Flow control
  • Inlet conditions
  • Jet near-field

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