Sites

http://www.youtube.com/watch?v=XKRj-T4l-e8

http://www.youtube.com/watch?v=cPALfz-6pnQ

https://www.youtube.com/watch?v=aWAjLOwOHU0

http://www.acs.psu.edu/drussell/Demos/TuningFork/fork-modes.html

Doppler:

http://www.lon-capa.org/~mmp/applist/doppler/d.htm

http://falstad.com/ripple/