Hydrodynamic instabilities of activity-balanced binary suspensions

We have built a mean-field kinetic model to study the underlying hydrodynamic instabilities in dilute, activity-balanced pusher-puller binary suspensions that produce near-zero mean extra stress. We have successfully demonstrated that mixing pushers and pullers in such binary systems may lead to much richer behaviors than a simple neutralization process due to the cancellation of stresslets from both species. Also, we find the instability mechanisms to be different from those derived for pure pushers or pullers, where a net extensile extra stress typically indicates unstable dynamics.