Finite-size radiation force correction for inviscid spheres in standing waves

Area of Science:

• Acoustics
• Fluid Dynamics
• Physics

Background:

• The Yosioka and Kawasima approximation (1955) describes acoustic radiation force on small liquid spheres.
• This approximation assumes inviscid fluids and negligible thermal dissipation.
• It posits force is proportional to sphere volume, making levitation size-independent.

Purpose of the Study:

• To introduce a correction term to the Yosioka and Kawasima approximation.
• To improve the accuracy of acoustic radiation force calculations for small liquid spheres.
• To investigate the influence of sphere radius, density, and sound velocity on the force.

Main Methods:

• Developed a theoretical analysis introducing a correction term proportional to the square of the sphere's radius.
• Compared the improved approximation with exact partial-wave-series calculations.
• Evaluated the significance of the correction term based on fluid properties.

Main Results:

• A small correction term proportional to the square of the sphere's radius was introduced.
• The significance of this term depends on the relative density and sound velocity of the sphere.
• The improved approximation shows good agreement with exact calculations for ideal fluid spheres.

Conclusions:

• The new approximation offers enhanced accuracy for acoustic radiation force on small liquid spheres.
• The correction term refines predictions, particularly for spheres where radius-dependent effects are non-negligible.
• This work provides a more precise tool for acoustic levitation studies.