Sound emission from a mesh triangle or vertex


I am pretty new to BEMP, and probably this is a silly question, but is better to ask the experts than to be stuck on a loop of trial and error indefinitely…

In this tutorial: Jupyter Notebook Viewer we have scattering of an incident plane wave. But if want the opposite: emit a monopole sound source from a triangle or vertex of the sphere to the outside world?

All I want to do is to emit a sound wave from a triangle or vertex of the boundary mesh to the outside and place some probes on the outside world around the sphere and measure the acoustic pressure on each one.

What is the best way to emit the sound from a boundary triangle or vertex

As for the acoustic pressure, it is simply calculating the magnitude, right?

These are probably silly questions, but I am giving my first steps into BEM, BEMPP, Helmoltz equiations and so on.

Thanks in advance.

Best regards,