Simulation Doppler Effect

Vollversion 1.0 - © 2002 Steffen Maus und Daniel Roth - All rights reserved!!

While emitting circular waves (phase velocity c) a source is moving with a constant velocity v. Depending on the position of an observer a frequency change (the so called "Doppler Effect") can be observed.

By moving the mouse, the mouse position, the elapsed time t and the the wave period T can be displayed.

Parameter changes have to be confirmed by hitting the ENTER key.

  • The background of the animation and the appearence of the emitter can be changed by editing the ".gif" bitmap files in the directory.
  • This Applet is "scriptable". This means that it can be configured and controled by using JavaScript methods inside the embedding web page. More information about scripting can be found in the file scripting.html.

    The following methods are available:

      • jsStart()
      starts simulation/animation

      jsStop()
      stops simulation/animation

      jsSetVisible(state,element)
      make user interface elements visible or invisible:

        state = "yes": make user interface element visible
        state = "no": make user interface element invisible

        element = "VBox": text field for velocity input
        element = "tOutput": overlay display of coordinates, time and frequency
        element = "Start": button to start/stop the simulation

      jsSetC(value)
      set wave phase velocity (default value = 10)

      jsSetV(value)
      set emitter velocity relative to wave phase velocity (default value = 0.4)

      jsSetT(value)
      set wave period (default value = 1.5s)

      jsSetDt(value)
      set time step for numerical caluclation (default value = 0.1s)