How long does it take water to flow through a tube under gravity?

[maxtor101]

Hi all!

If I had a tube with diameter x cm, filled with water, how would I calculate the time it takes for a volume V of the water to pass a point in the tube, flowing completely due to gravity.

Thanks

 

[Simon Bridge]

Assuming laminar flow and neglecting viscosity? You also need the height of the inflow end above the outflow end - then it's conservation of energy.