Where?

[Joe Baker]

I don't think the information you seek is fully known by anyone -- just too many variables involved. But you can find a lot of good info at http://www.rickdenney.com/the_tuba_sound.htm. Rick, in case you are unfamiliar with him, is our Resident Genius. There's a lot of other interesting tuba info on his site.
_______________________________
Joe Baker, who marvels that he has not been dubbed "Resident Doofus"

[Chuck(G)]

Since I don't know what your background is (i.e., can you handle graduate-level calculus), or to what depth you want to go, it's hard to make a good recommendation that works. But here's some stuff thrown out to you at random:

Art Benade's book "Fundamentals of Musical Acoustics", published by Dover, is a good place to start. Thomas Rossing and Neville Fletcher's "Physics of Musical Instruments" is more of a college-level textbook but has some good stuff. Musical Acoustics by Donald E Hall and Acoustics and the Performance of Music by Jürgen Meyer are a couple of texts you might look at.

Nick Drozdoff has some Realaudio lectures:

http://www.geocities.com/Vienna/3941/lectures.html

Jim Donaldson has reproduced some of Ren Schilke's papers:

http://www.dallasmusic.org/schilke/index.html

CCRMA at Stanford has some online stuff, though most of it is hardcopy:

http://ccrma.stanford.edu/marl/

There is a ton of online college-course lecture notes, but here's a great little online course from the University of New South Wales in Australia:

http://www.phys.unsw.edu.au/music/