Acoustic radiation torque on a particle in a fluid: An angular spectrum based compact expression.

Area of Science:

• Acoustics
• Fluid Dynamics
• Particle Physics

Background:

• Acoustic radiation torque (ART) is crucial for manipulating microparticles.
• Existing methods for ART calculation can be complex, especially for arbitrary particle shapes and acoustic fields.
• Efficient computation is needed for practical applications in acoustics and microfluidics.

Purpose of the Study:

• To derive compact analytical formulas for three-dimensional acoustic radiation torque (ART).
• To enable direct computation of ART on arbitrarily shaped particles in arbitrary acoustic fields.
• To facilitate ART determination when the acoustic field is known in a source plane.

Main Methods:

• Derivation of analytical formulas for ART.
• Utilizing angular spectrum based beam shape coefficients.
• Incorporating partial wave coefficients for computation.

Main Results:

• A set of compact analytical formulas for ART has been successfully derived.
• The formulation allows direct computation of ART from source plane acoustic field data.
• The method is applicable to particles of arbitrary shape and insonified by arbitrary acoustic fields.

Conclusions:

• The derived formulas offer a simplified and direct approach to calculating ART.
• This work provides a valuable tool for researchers in acoustic manipulation and related fields.
• The formulation is particularly advantageous when acoustic fields are characterized at the source plane.