Other aspects of transient flow in pipes

Any sort of model of these pressure transients gives no idea of the details of the real system. For instance the pressure transients in the metal of the pipe carry on running backwards and forwards at the same time as those in the water. They are easily detectable using strain gauges and show how much faster the wave fronts move in the metal than they do in the water.

 

In real pipe-work there will elbows and tees and these will produce reflections that just add to the general complexity.

 

I gave the impression that the void was at the valve but, depending on the configuration of the pipe, especially the slope, the void could be anywhere. Even when it is at the valve the void will not have a simple plane face but will have a ramp if the pipe is horizontal and be hollow[1] if the pipe is vertical.