Turbulent jet stability increased by ribs inside the nozzle – Stereo PIV measurement one diameter past the nozzle

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F49777513%3A23210%2F21%3A43962849" target="_blank" >RIV/49777513:23210/21:43962849 - isvavai.cz</a>
Result on the web
<a href="https://www.matec-conferences.org/articles/matecconf/pdf/2021/14/matecconf_pse2021_00006.pdf" target="_blank" >https://www.matec-conferences.org/articles/matecconf/pdf/2021/14/matecconf_pse2021_00006.pdf</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1051/matecconf/202134500006" target="_blank" >10.1051/matecconf/202134500006</a>

Result language
angličtina
Original language name
Turbulent jet stability increased by ribs inside the nozzle – Stereo PIV measurement one diameter past the nozzle
Original language description
We observe that decreasing the inner nozzle surface by adding longitudinal ribs increases the jet stability in terms of the amount of turbulent kinetic energy in the near shear layer. We try to explain our observation as a stabilization effect of secondary flow vortices emerging in the corners of the ribs. These stream-wise vortices damage the development of larger-scale structures in the near shear layer. This explanation is supported by autocorrelation function of the stream-wise velocity component, which displays slightly smaller integral length-scale in the case with ribs than in the case of smooth nozzle. The experiment is performed at Reynolds number 2.2 × 105 (based on the nozzle diameter 50 mm); the Stereo-PIV (Particle Image Velocimetry) measurement takes place at the plane perpendicular to the jet axis one diameter past the nozzle exit. Optical 3D scanner controls the real nozzle geometry. This article presents preliminary measurement at single position and single velocity only; further exploration of this problem is needed.
Czech name
—
Czech description
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Project
<a href="/en/project/EF16_026%2F0008389" target="_blank" >EF16_026/0008389: Research Cooperation for Higher Efficiency and Reliability of Blade Machines</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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