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Updated: Jun 28, 2026

Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics
Published on: August 27, 2013
Statistics and morphologies of stable droplets in scalar active fluids
Kathrin Hertäg1, Joshua F Robinson2,3, Thomas Speck1
1University of Stuttgart, Institute for Theoretical Physics IV, Heisenbergstr. 3, 70569 Stuttgart, Germany.
None:
Conventional phase segregation is controlled by a positive interfacial tension, which implies that the system relaxes towards a state in which the interfacial area (or length) is minimized, typically manifesting as a single droplet that grows with the system size. Intriguingly, the extension of the underlying Model B paradigm by two nonpotential terms (Active Model B+) is able to describe the stable coexistence of many finite droplets. Here we numerically study Active Model B+ in the vicinity of the transition between a single droplet (macrophase segregation) and multiple droplets (microphase segregation). Our results show that, although noise shifts transitions, the overall agreement with the mean-field theoretical predictions is very good. We find a strong correlation of droplet properties with a single parameter that determines the number, density, and fractal dimension of droplets. Deeper inside the domain of microphase segregation we observe another transition to a hexagonal lattice of regular droplets.
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