Phase-shift expansions for approximate radiation forces on solid spheres in inviscid-acoustic standing waves

Area of Science:

• Acoustics
• Fluid Dynamics
• Physics

Background:

• Acoustic radiation forces are crucial in acoustics and fluid dynamics.
• Previous work utilized scattering phase shifts for traveling wave scenarios.
• Understanding forces on spheres in standing waves requires specific theoretical frameworks.

Purpose of the Study:

• To extend the application of acoustic radiation forces to spheres in inviscid standing waves.
• To derive simplified expressions for radiation forces on various sphere types (solid, fixed-rigid, movable-rigid).
• To investigate finite-size corrections to low-frequency acoustic scattering approximations.

Main Methods:

• Utilizing scattering phase shifts, adapted for standing wave conditions.
• Applying low-frequency truncated expansions to phase shift expressions.
• Analyzing acoustic radiation forces on spheres of finite density.

Main Results:

• Derived simple, tractable expressions for acoustic radiation forces on spheres in standing waves.
• Identified leading finite-size corrections to the Rayleigh scattering approximation.
• Demonstrated the applicability of the phase shift method to standing wave phenomena.

Conclusions:

• The scattering phase shift approach is effective for analyzing acoustic radiation forces in standing waves.
• The derived expressions provide a more accurate understanding of forces on spheres, including finite-size effects.
• This work advances the theoretical basis for acoustic manipulation and scattering phenomena.