Lagrangian statistics of light particles in turbulence
| Autor: | Yoshiyuki Tagawa, Julian Martinez Mercado, Chao Sun, Detlef Lohse, Vivek N. Prakash |
|---|---|
| Přispěvatelé: | Physics of Fluids, Faculty of Science and Technology |
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Homogeneous isotropic turbulence Turbulence Mechanical Engineering IR-81790 Fluid Dynamics (physics.flu-dyn) Computational Mechanics Direct numerical simulation FOS: Physical sciences Particle-laden flows Reynolds number METIS-288413 Physics - Fluid Dynamics Condensed Matter Physics Physics::Fluid Dynamics symbols.namesake Water tunnel Mechanics of Materials Particle tracking velocimetry Statistics symbols Stokes number |
| Zdroj: | Physics of fluids, 24(5):055106. American Institute of Physics |
| ISSN: | 1070-6631 |
| Popis: | We study the Lagrangian velocity and acceleration statistics of light particles (micro-bubbles in water) in homogeneous isotropic turbulence. Micro-bubbles with a diameter of 340 microns and Stokes number from 0.02 to 0.09 are dispersed in a turbulent water tunnel operated at Taylor-Reynolds numbers (Re) ranging from 160 to 265. We reconstruct the bubble trajectories by employing three-dimensional particle tracking velocimetry (PTV). It is found that the probability density functions (PDFs) of the micro-bubble acceleration show a highly non-Gaussian behavior with flatness values in the range 23-30. The acceleration flatness values show an increasing trend with Re, consistent with previous experiments (Voth et al., JFM, 2002) and numerics (Ishihara et al., JFM, 2007). These acceleration PDFs show a higher intermittency compared to tracers (Ayyalasomayajula et al., Phys. Fluids, 2008) and heavy particles (Ayyalasomayajula et al., Phys. Rev. Lett., 2006) in wind tunnel experiments. In addition, the micro-bubble acceleration autocorrelation function decorrelates slower with increasing Re. We also compare our results with experiments in von Karman flows and point-particle direct numerical simulations with periodic boundary conditions. 13 pages, 9 figures, revised manuscript |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|