MAMEWorld Forums - The Loony Bin - Did someone say sucking pressure on a garden hose?

With the mention of a garden hose and sucking pressure, I was kinda imagining this thread degenerating in a different direction than it is...

But as it is...

>you'd only need enough pressure to overcome the surface tension.

WHa? Surface tension forces are not even a factor except at the mouth of the pipe, which are ignored because they approach zero in relevance.

where:
Φ is the volumetric flow rate
V is a volume of the liquid poured (cubic meters)
t is the time (seconds)
v is mean fluid velocity along the length of the tube (meters/second)
x is a distance in direction of flow (meters)
R is the internal radius of the tube (meters)
ΔP is the pressure difference between the two ends (pascals)
η is the dynamic fluid viscosity (pascal-second (Pa·s)),
L is the total length of the tube in the x direction (meters).

You'll note that the distance over which the flow rate is calculated is in the denominator, and pressure is in the numerator, meaning with the immense distance needed to travel, the corresponding pressure would have to be immense. Without even calculating it, the hose burst strength would be exceeded a million fold before you could push a single drop of water out at the other side.

edit: That being said, an Archimedes Screw would negate the need for pressure.. and that's what italie and I are working on. He said he was good at that, so that's where we are.

Edited by Gatinho (07/24/11 06:14 AM)