Unused U_cone Variable in BEMPP Loudspeaker Tutorial

Applications
1

Hi everyone,

I have a question about the loudspeaker tutorial in the bempp-acoustic-tutorials by mscroggs.

In the code, U_cone is defined as follows:

U_cone = 0.001 # Amplitude of the time-harmonic velocity of the cone in m/s

However, it doesn’t seem to be used anywhere in the code. Should U_cone be multiplied by n[2] in the following line?

@bempp.api.complex_callable
def u_total_callable(x, n, domain_index, result):
if domain_index == 2:
result[0] = n[2] # Should this be result[0] = U_cone * n[2]?
else:
result[0] = 0

And then, u_total is defined as:
u_total = bempp.api.GridFunction(spaceU, fun=u_total_callable)
u_total.plot()

I’d appreciate any clarification on whether U_cone should be included here.

Thank you!

2

Hello,

I came to the same question trying to adapt this example to my needs (open baffle directivity).

There is another post suggesting to apply the cone velocity on the BEM solver results : @tchoum using-bempp-to-calculate-far-field-sound-pressure-around-a-hollow-cube-with-imported-surface-velocities

Did you get some answers or did you come to a conclusion on it?

3

Hi,

I think they just forgot to put u_cone in the function u_total_callable, but you can set it as @Kevin did. Easiest thing is to multiply the results with the velocity of the cone. You won’t need to re-compute the BEM if you decide to change your speaker parameters.

I made a toolbox that automate the process (definition of domains and computation at evaluation points) combined to a lumped-element solver. It is mostly aimed at speaker design, but if it can be of any help: https://electroacpy.readthedocs.io