Causal mechanisms of drop breakup in turbulent flows

TL;DR

This paper investigates how turbulence causes drops and bubbles to break up, using a new analytical model based on flow decomposition that links flow intermittency to breakup statistics.

Contribution

It introduces a flow decomposition approach to model drop breakup, revealing the causal role of turbulence intermittency in breakup processes.

Findings

The outer flow drives drop deformation independently of drop dynamics.

The inner flow dissipates interfacial energy through turbulent eddies.

The analytical model matches numerical simulation results for breakup statistics.

Abstract

The fragmentation of drops and bubbles in turbulence determines the rate of many processes in engineering and environmental fluid flows. The nonlinear coupling between interfacial and hydrodynamic stresses poses a fundamental difficulty to model reduction, which we here address by decomposing the flow into outer and inner fields. We show that the outer field is independent of the drop dynamics and drives deformation, whereas the inner field responds to the deformation by dissipating the interfacial energy through the genesis of turbulent eddies. Drawing from these observations, we derive a simple analytical model that reproduces the breakup statistics obtained from ensembles of direct numerical simulations of drops and bubbles. Our results reveal a causal link between the intermittency of turbulent flows and the memoryless breakup statistics.