Quantitative concentration measurements in a turbulent helium jet using rainbow schlieren deflectometry
| Autor: | Ajay K. Agrawal, C. Taber Wanstall, Joshua A. Bittle |
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| Rok vydání: | 2021 |
| Předmět: |
Fluid Flow and Transfer Processes
Jet (fluid) Materials science Turbulence Computational Mechanics General Physics and Astronomy chemistry.chemical_element Reynolds number Laminar flow Mechanics 01 natural sciences Signal 010305 fluids & plasmas Physics::Fluid Dynamics 010309 optics symbols.namesake chemistry Mechanics of Materials Schlieren 0103 physical sciences symbols Rayleigh scattering Helium |
| Zdroj: | Experiments in Fluids. 62 |
| ISSN: | 1432-1114 0723-4864 |
| DOI: | 10.1007/s00348-021-03154-2 |
| Popis: | Rainbow schlieren deflectometry (RSD) is applied to acquire quantitative concentration measurements in a turbulent environment for the first time. RSD methodology is developed and validated using Rayleigh scattering data available in the literature. Experiments were performed in an initially laminar, momentum-driven helium jet injected into ambient air. Full-field measurements are acquired that span the laminar, transition, and fully turbulent regions of the jet. The RSD results are shown to provide accurate measurements in each region and also confirm the self-similar nature of the fully turbulent jet. Analysis shows that the transition from laminar to turbulent flow occurs across an axial span that decreases with increasing Reynolds number. Experiments with a long exposure time were conducted to evaluate the limitations of hardware averaging of the RSD signal in comparison with software averaging. |
| Databáze: | OpenAIRE |
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