Microbubble Clustering in Turbulent Flow

by Enrico Calzavarini et al. arXiv.org E-print Archive, 27 Jul 2006 Single-point hot-wire measurements in the bulk of a turbulent channel have been performed in order to detect and quantify the phenomenon of preferential bubble accumulation. We show that statistical analysis of the bubble-probe colliding-times series can give a robust method for investigation of clustering in the bulk regions of a turbulent flow where, due to the opacity of the flow, no imaging technique can be employed. We demonstrate that micro-bubbles (R0 ≃ 100 μm in a developed turbulent flow, where the Kolmogorov length-scale is ≃ R0, display preferential concentration in small scale structures with a typical statistical signature ranging from the dissipative range, O(), up to the lower end of inertial range, O(100). A comparison with Eulerian-Lagrangian numerical simulations is also performed and arising similarities and differences are discussed. Read more