Wavelet-based algorithm for correction of beam-steering artefacts in turbulent flow imaging at elevated pressures
| Autor: | Jonathan H. Frank, Bo Zhou, Erxiong Huang, Adam James Ruggles |
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| Rok vydání: | 2019 |
| Předmět: |
Fluid Flow and Transfer Processes
Materials science Turbulence Acoustics Beam steering Computational Mechanics General Physics and Astronomy Laser Residual 01 natural sciences Noise (electronics) 010305 fluids & plasmas law.invention Physics::Fluid Dynamics 010309 optics symbols.namesake Wavelet Mechanics of Materials law 0103 physical sciences symbols Physics::Accelerator Physics Rayleigh scattering Image resolution |
| Zdroj: | Experiments in Fluids. 60 |
| ISSN: | 1432-1114 0723-4864 |
| DOI: | 10.1007/s00348-019-2782-6 |
| Popis: | Beam steering by index-of-refraction gradients poses a significant challenge for laser-based imaging measurements in turbulent reacting and non-reacting flows, particularly at elevated pressures. High fidelity imaging and quantitative data interpretation in turbulent flows can be considerably impeded by artefacts generated from beam steering. A wavelet-based filtering scheme has been developed to recover the underlying turbulent flow structures from imaging measurements containing severe beam-steering artefacts. This analysis technique is equally applicable to imaging measurements in reacting and non-reacting flows. It is demonstrated using mixture fraction measurements in a transient turbulent jet flow at 8 bar using Rayleigh scattering imaging at a repetition rate of 100 kHz. The corrected images reveal the temporal evolution of flow structures with negligible residual beam-steering artefacts. Tests of the sensitivity of the wavelet-based filtering scheme to noise and spatial resolution indicate that it is a robust analytic tool for correcting severe beam-steering artefacts commonly encountered in laser-based imaging measurements at elevated pressures. |
| Databáze: | OpenAIRE |
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