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Updated: Jul 6, 2026

The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
Wake attenuation in large Reynolds number dispersed two-phase flows
Frédéric Risso1, Véronique Roig, Zouhir Amoura
1Institut de Mécanique des Fluides, UMR 5502 CNRS/INP/UPS Allée Camille Soula, 31400 Toulouse, France. frederic.risso@imft.fr
In high Reynolds number two-phase flow, bubble wakes decay exponentially. Wake length depends on bubble size and drag, surprisingly unaffected by bubble concentration within a specific range.
Area of Science:
- Fluid dynamics
- Multiphase flow
- Experimental physics
Background:
- Dispersed two-phase flow dynamics are significantly influenced by wakes behind moving particles.
- Wake lengths in such flows are notably shorter than those of isolated bodies.
Purpose of the Study:
- Investigate the attenuation of wakes in dispersed two-phase flow.
- Determine the dependence of wake attenuation on body Reynolds number and volume fraction (alpha).
Main Methods:
- Experimental investigations of homogeneous bubble swarms and fixed random sphere arrays.
- Analysis of wake characteristic length and decay rates.
- Comparison with isolated body wakes in turbulent flow.
Main Results:
- Wakes in homogeneous bubble swarms exhibit exponential decay.
- Characteristic wake length scales with bubble diameter (d) and drag coefficient (Cd).
- Wake attenuation is independent of volume fraction (alpha) for 10⁻² ≤ alpha ≤ 10⁻¹.
- Wakes in fixed sphere arrays show stronger attenuation than isolated sphere wakes but similar decay to bubble swarms.
Conclusions:
- Multi-body interactions dominate wake dynamics in dispersed two-phase flows, leading to faster decay than turbulent fluctuations.
- Proposed decomposition of velocity fluctuations to study multi-body interaction mechanisms.
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