| If the source of sound (or light) is moving, the wave length l
before the source becomes shorter and the frequency higher, while behind
the moving source it is vice versa. This phenomenon is called
Doppler-effect. If the speed of the source exceeds the speed of the
emitted wave, a conical shock wave emerges. Move the slider to change
the Mach number, M = vsource/vsound
and see the effect. The drawing shows spherical waves emitted by the
source moving to the right at different moments of time. |