Kolmogorov Turbulence Coexists with Pseudo-Turbulence in Buoyancy-Driven Bubbly Flows

TL;DR

This paper explores how buoyancy-driven bubbly flows exhibit both Kolmogorov turbulence and pseudo-turbulence, revealing energy transfer mechanisms through high-resolution simulations and phenomenological analysis.

Contribution

It demonstrates the coexistence of Kolmogorov turbulence and pseudo-turbulence in bubbly flows and identifies the conditions under which each regime dominates.

Findings

Kinetic energy spectrum follows Kolmogorov $-5/3$ scaling at certain scales.

Pseudo-turbulence physics is observed at scales smaller than the dissipation scale.

High-resolution simulations confirm the dual turbulence regimes.

Abstract

We investigate spectral properties of buoyancy driven bubbly flows. Using high-resolution numerical simulations and phenomenology of homogeneous turbulence, we identify the relevant energy transfer mechanisms. We find: (a) At high enough Galilei number (ratio of the buoyancy to viscous forces) the kinetic energy spectrum shows the Kolmogorov scaling with a power law exponent $-5/3$ for the range of scales between the bubble diameter and the dissipation scale ($\eta$). (b) For scales smaller than $\eta$, the physics of pseudo-turbulence is recovered.