Direct numerical simulation of non-Newtonian fluid droplets in homogeneous isotropic turbulence

Abstract

Droplet breakup and dispersion in turbulent flows have broad applications in engineering, yet the interaction between turbulence and non-Newtonian droplet breakup still lacks understanding. This study investigates the breakup dynamics of Newtonian and non-Newtonian droplets in forced homogeneous isotropic turbulence using high-fidelity numerical simulations based on the mass-conservation level set method. The simulations consider the effects of shear-thinning viscosity and turbulent stress on droplet deformation, fragmentation, and distribution. The results show that non-Newtonian droplets exhibit higher resistance to fragmentation, forming larger fragments due to faster vortex dissipation and reduced turbulent stress at the interface. In contrast, Newtonian droplets undergo rapid fragmentation, resulting in smaller, more uniform droplets. This work provides new insights into turbulence-induced droplet breakup mechanisms and offers a foundation for future optimization of non-Newtonian fluid applications.