2017 journal article

Evaluation of bubble-induced turbulence using direct numerical simulation

INTERNATIONAL JOURNAL OF MULTIPHASE FLOW, 93, 92–107.

By: J. Feng n & I. Bolotnov n 

co-author countries: United States of America πŸ‡ΊπŸ‡Έ
author keywords: DNS; Deformable bubble; Turbulent intensity; Homogeneous turbulent flow; Bubble-induced turbulence
Source: Web Of Science
Added: August 6, 2018

The presented research evaluates the interaction between a single bubble and homogeneous turbulent flow using direct numerical simulation (DNS) approach. The homogeneous single-phase turbulence is numerically generated by passing a uniform flow through grid planes. The turbulence decay rate is compared with experiment-based correlation. The single phase turbulence is then used as an inflow boundary condition for a set of single bubble studies. By estimating the turbulent field around the fully resolved bubble, the effects of bubble deformability, turbulent intensity and relative velocity on the bubble-induced turbulence are investigated. The existence of bubble creates new vortices in the wake region and the enhancement of turbulence is observed in the region behind the bubble. The results show that the magnitude of the turbulence enhancement would increase as the bubble encounters larger liquid turbulent intensity or higher relative velocity. Set of bubble Weber numbers from 0.34 to 3.39 are used to investigate the effect of bubble deformability. The more deformable bubble is the higher the increase in the magnitude of the turbulence enhancement behind the bubble. This research provides systematic insight on the bubble-induced turbulence (BIT) mechanism and is important for multiphase computational fluid dynamics (M-CFD) closure model development.