Published 4 issues per year
ISSN Online: 2152-209X
Visualization of the processes of development and turbulent breakdown of a low speed round jet
ABSTRACT
Results of experimental investigations of the influence of longitudinal streaky structures on the turbulization process of a a low speed round laminar jet are presented in this work. Qualitative characteristics of the jet development with the application of a smoke visualization of the flow pattern in the jet and video filming of cross and longitudinal sections of the jet, illuminated by a laser sheet at the image stroboscoping. It is shown that streaky structures can be generated directly in the nozzle exit section, and their interaction with the Kelvin-Helmholtz ring vortices leads to the appearance of azimuth beams (Λ- or Ω-vortex structures) of a type of a distortion of the 2D Tollmien-Schlichting wave at a nonlinear stage of classical transition in the near-wall flows. The influence of the jet outflow velocity and acoustic excitation on the jet turbulization is considered.
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Shestakov Maxim V., Dulin Vladimir M., Tokarev Mikhail P., Sikovsky Dmitrii Ph., Markovich Dmitriy M., PIV study of large-scale flow organisation in slot jets, International Journal of Heat and Fluid Flow, 51, 2015. Crossref