Forces, torques, and motion everywhere in an ultrasonic standing wave field

Ultrasonic standing waves are used to align and manipulate non-spherical objects. In a previous report, simulations were performed to determine the forces and torques on rod-shaped objects located in stable positions at a standing wave node. Here I determine the forces and torques at all positions in the standing wave field. I present simple expressions with two adjustable parameters that fit these forces and torques. I then use the force and torque expressions to predict the trajectories of objects as a function of time.