Microgravity Science and Technology

, Volume 27, Issue 3, pp 207–220 | Cite as

Turbulent Bubble Jets in Microgravity. Spatial Dispersion and Velocity Fluctuations

  • Pau Bitlloch
  • Xavier Ruiz
  • Laureano Ramírez-Piscina
  • Jaume Casademunt
Original Article

Abstract

A detailed statistical analysis of bubble dispersion in turbulent jets based on data from drop tower experiments is presented here. A stochastic model is also introduced in order to capture these statistics to a large extent, treating bubbles as passive tracers with a local diffusivity given by a k- ε description of the turbulence. Bubble-bubble and bubble-flow interactions are neglected. Simple scaling analysis suggests that this approach is justified sufficiently far downstream. It is also found that, although interactions cannot be neglected very close to the inlet, the model predictions for the overall spatial distribution of the bubble ensemble are compatible with data within experimental uncertainty, and within the limited statistics of the experiments. In addition, the velocity fluctuations from the same experiments are analyzed, obtaining the local standard deviation of bubble velocities. We also find good agreement between experimental data and the effective model. Slight deviations between the model predictions and the experimental data are found at the jet margins, concerning the dependence on Reynolds number of jet angle and the relative velocity fluctuations. Consequently, significant bubble-flow interactions seem to be confined at the boundaries of the jets.

Keywords

Turbulent jet Bubble dispersion Bubble interactions Microgravity Drop tower Velocity fluctuations 

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Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  • Pau Bitlloch
    • 1
  • Xavier Ruiz
    • 2
    • 4
  • Laureano Ramírez-Piscina
    • 3
    • 4
  • Jaume Casademunt
    • 1
    • 4
  1. 1.Departament d’Estructura i Constituent de la MatèriaUniversitat de BarcelonaBarcelonaSpain
  2. 2.Departament de Química, Física i InorgànicaUniversitat Rovira i VirgiliTarragonaSpain
  3. 3.Departament de Físca AplicadaUniversitat Politècnica de CatalunyaBarcelonaSpain
  4. 4.Institut d’Estudis Espacials de CatalunyaBarcelonaSpain

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