Speaker
Description
Electrohydrodynamic flows in emulsions provide a controllable setting for studying driven non-equilibrium systems. In this work, we introduce an oil-in-oil emulsion that enables systematic control of EHD behavior by tuning the electrical conductivity of the continuous phase while maintaining nearly constant viscosity and dielectric contrast. At low electric fields, droplet deformations are consistent with leaky-dielectric theory across a range of conductivity ratios, providing direct experimental validation of drop-deformation models. At higher fields, the system undergoes a transition to a dynamically disordered state characterized by collective droplet motion and strong spatiotemporal fluctuations. We quantify this regime using particle image velocimetry (PIV), differential dynamic microscopy (DDM), and rheometry, revealing scale-invariant velocity fluctuations and power-law energy spectra at low Reynolds number, i.e., an unusual microscale turbulence. These results represent a useful model system for studying driven non-equilibrium soft-matter.
| Keyword-1 | Electrohydrodynamics |
|---|---|
| Keyword-2 | Non-equilibrium soft matter |
| Keyword-3 | Microscale turbulence |