Dynamic radiation force of acoustic waves on solid elastic spheres

Area of Science:

• Acoustics
• Fluid Dynamics
• Solid Mechanics

Background:

• The dynamic radiation force is crucial in wave-structure interactions.
• Fluid nonlinearity can alter acoustic wave propagation and forces.
• Previous studies often neglect fluid nonlinear effects in radiation force calculations.

Purpose of the Study:

• To investigate the dynamic radiation force on solid elastic spheres under a bichromatic plane wave.
• To analyze the impact of fluid nonlinearity on this force.
• To explore resonance phenomena in the dynamic radiation force spectrum.

Main Methods:

• Solving wave scattering for a sphere using the quasilinear approximation.
• Integrating the momentum flux tensor at the difference frequency over the sphere's boundary.
• Applying the developed theory to aluminum, silver, and tungsten spheres.

Main Results:

• Fluid nonlinearity plays a major role, inducing a parametric amplification regime.
• Resonances in the dynamic radiation force spectrum were observed.
• These dynamic resonances exhibit larger amplitude and better shape than static ones.

Conclusions:

• Fluid nonlinearity is a critical factor in bichromatic wave-induced dynamic radiation forces.
• The study demonstrates enhanced resonance characteristics in the dynamic regime.
• The findings have implications for understanding acoustic radiation forces in nonlinear fluids.