Dynamics of internally driven complex fluids

Complex fluid is a very broad class of matter, including amorphous solids, polymer suspension and many biological tissues. The rich dynamics of complex fluids under external driving force have been studied extensively. However, deformation in complex fluids is often driven internally by constituents in many natural and artificial systems, such as tissue migration and flow of densely packed self-propelled particles. Here, we develop a numerical model to study the dynamics and mechanical properties of a complex fluid subject to internal drive. The results are relevant to activity-controlled dynamics of dense bacterial assemblies.