This is an animation of a bedload transport simulation.  The simulation is performed by direct simultaneous numerical integration of the equations of motion of each sediment grain. You will see that transport increases in response to a sweep event.

The animation is run by a Java applet:  Copyright (C) 1998-1999 by Klaus Ehrenfried. Click on the animation first and then you can manipulate the playback properties with the following commands.
Key Function
Running Stopped
SPACE-BAR Stop Restart
Dot (.) Stop & Set forward play Step forward & Set forward play
Comma (,) Stop & Set reverse play Step backward & Set reverse play
Plus (+) Increase animation speed
Minus (-) Decrease animation speed
Null (0) Set initial animation speed
(R) or (r) Toggle play direction: backward/forward