On Mon, 08 Dec 2014 08:07:40 -0700, Scott Dorsey <klu...@panix.com
> If you can do it 2D, writing a raytracer should be an afternoon's work,
> or you can just do it by hand with graph paper and a ruler. Or make a
> wave tank on yout kitchen table.
> It is so rare that 2D simulation would ever be useful for anything that I
> do not know if any actual 2D software out there.
> That's simple heterodyning, it's really got nothing to do with boundary
> conditions per se. Harry Olson's book on acoustical engineering has some
> discussion of nonlinearity due to compressability of air. This has been
> extensively studied because there are a number of very high pressure
> applications, such as compression drivers for horn speakers, where it
> becomes a major source of nonlinearity.
Thank you for your excellent reply. The final analyses will require 3D for
certain. Being a EE, I have no allegory [is that the right word?] to even
begin. I have NO idea what the basic constants are for AIR, or even what
to do with them to model this phenomenon.
The test setup will be launching variable 60kHz up to 100kHz into AIR,
from an aperture that will be several wavelengths across [From
RF/Microwave antenna designs I know how aperture, wavelength, etc combine
to create beam spreading based on those two. Sadly, when I had the
opportunity to learn about acoustics [see below] I didn't. Right now, I
have NO idea what the coefficients of attenuation are with distance, nor
how much energy it takes to start getting into that non-linear saturation
condition. Especially important is how to model the medium as it tries to
carry both this high energy. I do know that sound is a slippery critter
and any modeling will quickly turn into 3 dimensional math.
Are you skilled in acoustics enough to give me some basic terminology and
equations representing the compressibility/elasticity etc of AIR? And tell
me how to use them? Or provide some URL that has all this background in
the form of tutorial? Need basics here. I don't mind rederiving up from
basics to get there from here.
The water tank idea did NOT occur to me. Possibly because while developing
Non-invasive Medical Diagnostic Instrumentation [ultrasonic
echocardiography] we used water tanks and lasers to 'view' the 2MHz to
5MHz transducers' beams and I didn't notice that water compressed like air
and therefore didn't think it would display the non-linearities I'm trying
to find the effects of. [Yes, English is my first language] Try again: It
is my understandng that air can be driven into non-linearity fairly
easily. I wish to explore that condition. And have NO idea how to go about