[SMaLS] Still Playing with Sticks: Controlling Turbulent Flows with Compressibility

Speaker: Dimitrios Krommydas (Postdoctoral Fellow, Marchetti Group)

Title: Still Playing with Sticks: Controlling Turbulent Flows with Compressibility

Abstract: Motivated by experiments on activity-patterned, quasi-2D active suspensions that exhibit large
density variations, we develop a continuum theory of compressible active nematics—active suspensions of “sticks” with average orientation invariant under π rotations. Notably, a 1D isotropic limit of our model is sufficient to capture inhomogeneous steady-state density profiles, which—due to the extensile isotropic pressure—exhibit filament depletion in high-activity regions and accumulation in low-activity regions. The resulting large density differences are controlled by compressibility. Using compressibility as a tuning parameter we unveil a range of turbulent patterns, including novel dynamical steady states of 1D vortex "conveyor belts". Our numerical and analytical results provide a new pathway to control density variations and turbulent flows, thereby enabling direct control of active nematic suspensions.