Motion of Source Effects Frequency of Wave: an Exploration

[gstar2002]

i know that motion of source can change the frequency of wave.
constant speed motion will not change the wave progagation relative to water itself.but from the point of a observer at speed 0, the propagation speed will change. so my question is what will happen to frequency?
thanks for help. maybe the motion is then not wave.

 

[hikaru1221]

Suppose that the source doesn't move. In T, the source emits a full wavelength d = vT, where v is the propagation speed in moving medium. The wave front approaches the observer with speed v. So to pass the observer a distance d (= 1 wavelength), it takes time = d/v = T. So nothing changes The result is not surprising, as Doppler effect has nothing to do with propagation speed in the medium.