  Acoustic handling of nanoparticles in resonating acoustofluidic devices is
often impeded by the presence of acoustic streaming. For micrometer-sized
acoustic chambers, this acoustic streaming is typically driven from the
fluid-solid interface by viscous shear-stresses generated by the acoustic
actuation. AC electroosmosis is another boundary-driven streaming phenomena
routinely used in microfluidic devices for handling of particle suspensions in
electrolytes. Here, we study how streaming can be suppressed by combining
ultrasound acoustics and AC electroosmosis. Based on a theoretical analysis of
the electrokinetic problem, we are able to compute numerically a form of the
electrical potential at the fluid-solid interface, which is suitable for
suppressing a typical acoustic streaming pattern associated with a standing
acoustic half-wave. In the linear regime, we even derive an analytical
expression for the electroosmotic slip velocity at the fluid-solid interface,
and use this as a guiding principle for developing models in the experimentally
more relevant nonlinear regime that occurs at elevated driving voltages. We
present simulation results for an acoustofluidic device, showing how
implementing a suitable AC electroosmosis results in a suppression of the
resulting streaming in the bulk of the device by two orders of magnitude.
