Acoustic Contrast Factor

Abstract

The acoustic contrast factor ($Φ$) governs whether an object will be affected by the acoustic radiation force in an acoustic standing wave field. It is comprised of the density and speed of the sound of the object ($ρ$pand cp) and the surrounding medium ($ρ$0 and c0), as seen in the equation below. A positive contrast factor means that the object will move to a pressure node, while a negative factor will move the object toward a pressure antinode