These effects are the result of mechanical quantitative force on matter, relating to a physical rather than a chemical change. As the amplitude of ultrasound increases equilibrium becomes more difficult to restore.
Tissues containing gas have the greatest swings in variables.
Rotational circulatory flow of the fluid, i.e. microstreaming or spinning of intracellular particles. Leads to movement of particles in the direction of energy flow. Increased Pressure at pressure maxima leads to increased propagation speed. Leads to movement of particles and streaming in a complex way. Viscosity in the compression phrase is appreciably different than in the rarefraction phase.