Transport of micro-bubbles in turbulent shear flows

9th International Symposium on Cavitation

Gualtieri, P.^1 ; Battista, F.^1 ; Casciola, C.M.^1

Diaprtimento di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, Via Eudossiana 18, Roma

00184, Italy^1

关键词: Clustering properties;    Homogenous turbulent shear flow;    Near-wall region;    Rayleigh-Plesset equation;    Turbulent pipe flow;    Turbulent pressure fluctuations;    Turbulent shear flows;    Wall bounded flows;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/656/1/012018/pdf
DOI  :  10.1088/1742-6596/656/1/012018

来源: IOP

【 摘 要 】

The dynamics of micro-bubbles, which are typical in many industrial applications, is addressed by means the Direct Numerical Simulations (DNS) of two prototypal flows, namely a homogeneous shear flow and a fully developed pipe flows. This preliminary study has a two-fold purpose. The homogenous turbulent shear flow is useful to characterize the bubble dynamics in terms of their eventual clustering properties which is expected to be controlled by the Stokes number. The time history of the fluid pressure experienced by the bubbles during their evolution is recorded and successively employed to force the Rayleigh-Plesset equation [1]. The ensuing data are used to address a posteriori the bubble diameter statistics in view of bubble collapse induced by strong and intermittent turbulent pressure fluctuations. The turbulent pipe flow simulations serve to address the bubble dynamics in wall bounded flows. Here the bubbles are observed to accumulate in the near-wall region with different intensity depending on the bubble dimensions.