Abstract: A method for separating a second fluid or a particulate from a host fluid is disclosed. The method includes flowing the mixture through an acoustophoretic device comprising an acoustic chamber, an ultrasonic transducer, and a reflector. The transducer includes a piezoelectric material driven by a voltage signal to create a multi-dimensional acoustic standing wave in the acoustic chamber. A voltage signal is sent to drive the ultrasonic transducer in a displacement profile that is a superposition of a combination of different mode shapes that are the same order of magnitude to create the multi-dimensional acoustic standing wave in the acoustic chamber such that the second fluid or particulate is continuously trapped in the standing wave, and then agglomerates, aggregates, clumps, or coalesces together, and subsequently rises or settles out of the host fluid due to buoyancy or gravity forces, and exits the acoustic chamber.