Dear acousticians,
I have a question which is a bit general and maybe not specific to the k-wave software, but definitely something for acoustic people.
My question is whether it is logic that a plane wave, incident from an infinite air medium onto a rigid wall with an opening of 1.5m by 1m (nothing is in the opening, after the opening there is a again an infinite air medium - rigid wall separates the full space), results in a non-constant incident intensity level curve measured and averaged over the opening. I am wondering some time now why this is not constant? I thougth that the intensity and power in a plane wave are constant i.e. that is what I understood from my acoustics class.
The non-constant intensity profile is as follows : a constant intensity level of around 55dB for plane waves from 10 - 70Hz. Around 80Hz a sudden increase happens in the intensity values till around 100 Hz till a level of 85dB is reached. Hereafter the 85 dB remains more or less constant till 1000 Hz. For these simulations a 1Pa amplitude pressure sine waves is taken for the whole frequency range.
I would be very grateful I someone could give me more insight why this is so,....