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Développement de la PIV tomographique pour l’étude d’écoulements turbulents

Abstract : This research dissertation focuses on the developments of tomographic PIV (tomo-PIV) for the measurement of turbulent flows (Elsinga et al. 2006). It is based on the tomographic reconstruction of a volumic intensity distribution of tracer particles from projections recorded on cameras. Its main limitation is the appearance of ghost particles, ie reconstruction noise, which occurs when high tracer concentrations are required for high spatial resolution measurements. A study on the imaging conditions for tomo-PIV led us to propose an alternative approach to classical tomographic reconstruction: Particle Volume Reconstruction (PVR). PVR underlies a more physical, sparse representation of point particles, which lives halfway between infinitely small particles, and voxel blobs commonly used in tomo-PIV, which smoothed, can be used in 3D-PIV. Numerical simulations showed that PVRSMART outperforms tomo-SMART (Atkinson et al. 2009) especially in the case of seeding density greater than 0.06 ppp. We introduce a cross-correlation technique for 3D-PIV (FOLKI-3D) as an extension to 3D of the FOLKI-PIV algorithm (Champagnat et al. 2011). Numerical simulations of tomographic reconstruction characterized the robustness of the algorithm to specific tomographic noise. FOLKI-3D was found more robust to coherent ghosts than standard deformation algorithms. Experimental validation of PVR-SMART was performed on a turbulent air jet. Several seeding density conditions were used to compare the performance of tomo-SMART and PVRSMART on the near field region of the jet. With the given image pre-processing, PVR-SMART was found to yield velocity fields that are 50 % less noisy than tomo-SMART.
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https://hal.archives-ouvertes.fr/tel-01455219
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Submitted on : Friday, February 3, 2017 - 1:51:00 PM
Last modification on : Thursday, October 28, 2021 - 3:16:37 PM
Long-term archiving on: : Friday, May 5, 2017 - 1:14:56 PM

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  • HAL Id : tel-01455219, version 1

Citation

Adam Cheminet. Développement de la PIV tomographique pour l’étude d’écoulements turbulents. Mécanique des fluides [physics.class-ph]. Université Paris-Saclay, 2016. Français. ⟨NNT : 2016SACLX020⟩. ⟨tel-01455219v1⟩

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