Topic split from Sheck thread - water velocity

[phreaticus]

Just curious (I'm no math wiz.)....if you increase the flow in a tube that is, say, six feet in diameter, by 60 %...what does that do to water velocity?
I don't think it is linear...correct?

Actually, it WOULD be linear. Assuming the diameter of the tube remains constant, the "velocity" is the third dimension.

Example: your six-foot tube has an "area" of just over 28 square feet. If the water runs at two feet per second, you have a flow of 56 cubic feet per second. If the water speeds up 50%, or to three feet per second, your flow also increases 50%, to 84 cubic feet per second.

[phreaticus]

Sooooo.....what would the velocity be at 176 cfs (the extrapolated flow on 8/27/80)...in mph(or knots per hour?).......just for some perspective, in my brain, on how it was then as to how it was now, at 96 cfs? In that same size tube?
Is there a comparative formula?

[Shadowjack]

however you ADD it up. it's a lot of water coming out of that hole down there...



Eric

Velocity at 176 cubic feet per second in a tube EXACTLY six feet in diameter would be 6.224 feet per second or 4.242 miles per hour.

Velocity at 96 cubic feet per second in the same tube would be 3.395 feet per second or 2.314 miles per hour.

[phreaticus]

Now...(I'm enjoying this, as you probably figured out!)...what's the difference in "resistance" in a 4 mph flow of water vs. a 4mph flow of air?
What airspeed would be the equivalent, considering the density difference?

Water is said to be 784 times as dense as air. But I really don't think that means standing in a 4mph flow of water is like standing in a 3,000mph wind...

[Wizard]

Water is said to be 784 times as dense as air. But I really don't think that means standing in a 4mph flow of water is like standing in a 3,000mph wind...

Oh but it would if your body were plugging a pipe. Hydraulics, what a concept.

[aainslie]

Water is said to be 784 times as dense as air. But I really don't think that means standing in a 4mph flow of water is like standing in a 3,000mph wind...

Oh but it would if your body were plugging a pipe. Hydraulics, what a concept.

Really? You'd be equally willing to act as a plug in a pipe with a 3000 mph wind as in one with a 4 mph water flow?

I know which one I'd pick... I'd rather emulate toilet paper in a loo than a bullet in a high speed rifle!

[phreaticus]

lets not let this thread crash as most of them do when no one has an accurate answer.....so....what would it be?