Discussion Forum

Hello, everyone,

I am currently working on a simulation model with which I want to calculate the Acoustic Radiation Force on a particle in water. The corresponding calculation approach is taken from this publication: https://www.comsol.de/blogs/how-to-compute-the-acoustic-radiation-force/ The calculation is based on the solution of a linear acoustic problem where sound pressure, particle velocity, sound velocity and density are determined. From this, a second order acoustic pressure field is calculated, from which the Acoustic Radiation Force can then be calculated.

In my model, however, it is not a 2D axisymmetric setup, but a 3D setup. More precisely, it is a cylinder filled with water. The acoustic pressure field is generated by piezoelectric transducers, which are distributed asymmetrically on the bottom of the cylinder. The transducers are fed by arbitrary voltage signals in the time domain, resulting in a distinct focusing effect within the water at some points in time. This can be seen in the attached pictures. For a point in time where a clear focusing effect is obtained, I would like to calculate the Acoustic Radiation Force on an introduced particle according to the approach of A. Grinenko. However, due to the given time signals of the transducers I have to calculate the acoustic pressure field in the time domain. For this I use the physics "Pressure Acoustics, Transient (actd)", which leads to another difference compared to the publication mentioned above. When using the "Pressure Acoustics, Transient (actd)", however, unfortunately the sound velocity within the water is not determined, which means that the calculation proposed by A. Grinenko cannot be carried out.

This is the reason for my question: Is there a simple possibility to calculate the sound velocity in Comsol for the physics "Pressure Acoustics, Transient (actd)"? Does anyone see another solution for my problem?

Many greetings

Philipp