Considered is a cylinder channel with a single row of 10 aligned impinging jets, with exit flow in the axial direction at one end of the channel. For the present predictions, each jet is laminar with a Reynolds number of 200. An unsteady RANS solver is employed for predictions of flow characteristics within and nearby the 10 impingement jets. Spectrum analysis of different flow quantities shows frequencies associated with laminar jet and vortex oscillations, and evidence more orderly flow for Re=200, without the chaos and broad-band mixing associated with the turbulent flow when Re=15,000. Laminar flow spectra also evidence increased flow unsteadiness as cross-flows accumulate within the impingement channel with streamwise development as Z/D increases. In some cases, this increased unsteadiness manifests itself through the formation of multiple spectral peaks, in place of single peak spectra. As for the turbulent jet arrangements, unsteady, local static pressure gradient variations along interfaces between laminar jets and cross flow are also a key flow feature, which is connected to the initiation and development of the Kelvin-Helmholtz instability induced vortices.
Unsteady Structure and Development of a Row of Impingement Jets, Including Shear Layer and Vortex Development: Part 2 — Laminar Jets
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Yang, L, Ren, J, Jiang, H, & Ligrani, PM. "Unsteady Structure and Development of a Row of Impingement Jets, Including Shear Layer and Vortex Development: Part 2 — Laminar Jets." Proceedings of the ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. Volume 5A: Heat Transfer. Montreal, Quebec, Canada. June 15–19, 2015. V05AT11A023. ASME. https://doi.org/10.1115/GT2015-43074
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