  Colloidal suspensions in industrial processes often exhibit shear thickening
that is difficult to control actively. Here, we use piezoelectric transducers
to apply acoustic perturbations to dynamically tune the suspension viscosity in
the shear-thickening regime. We attribute the mechanism of dethickening to the
disruption of shear-induced force chains via perturbations that are large
relative to the particle roughness scale. The ease with which this technique
can be adapted to various flow geometries makes it a powerful tool for actively
controlling suspension flow properties and investigating system dynamics.
