Acoustophoretic devices for separating particles from a non-flowing host fluid are disclosed. The devices include a substantially acoustically transparent container and a separation unit, with the container being placed within the separation unit. An ultrasonic transducer in the separation unit creates a planar or multi-dimensional acoustic standing wave within the container, trapping particles disposed within the non-flowing fluid and causing them to coalesce or agglomerate, then separate due to buoyancy or gravity forces.