Flow behavior and odd viscosity of a suspension of chiral brownian particles

We consider a chiral fluid in two dimensions composed of Brownian disks interacting via a Lennard-Jones potential and a nonconservative transverse force, mimicking colloids spinning at a given rate. The system exhibits a phase separation between a chiral liquid and a dilute gas phase that can be characterized using a thermodynamic framework. We compute the equations of state and show that the surface tension controls interface corrections to the coexisting pressure predicted from the equal-area construction. Transverse forces increase surface tension and generate edge currents at the liquid-gas interface. This induces a complex response to external shear driving, also depending on the intrinsic chirality of the system with respect to the shear direction.

First, We found that chirality and external driving strength each other, producing a shear thinning behavior.

Second, when the direction of shear opposes the chirality, at high shear rates, the chiral fluid arranges into stripes, exhibiting increased positional and orientational order.

Lastly, chirality leads to an additional contribution to the viscous stress, known as odd viscosity, object of many recent investigations, which we characterize in the linear response regime.