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Beware the bubble’s burst (Bedrock damage at dam spillway)
Creation.com ^ | 24 October 2007(GMT+10) | David Catchpoole

Posted on 01/18/2012 8:39:46 AM PST by fishtank

Beware the bubble’s burst

Increased knowledge about cavitation highlights the destructive power of fast-flowing water

by David Catchpoole

Published: 24 October 2007(GMT+10)

This is the pre-publication version which was subsequently revised to appear in Creation 31(2):50–51.

When Britain’s Royal Navy ships were suffering considerable and unexplained damage to their ships’ propellers in WWI, physicists worked out that violent ‘bubble cavitation’1 was the cause. This happens because tiny bubbles grow and then collapse as a result of pressure variations in the turbulent water around a propeller. But nobody knew just how hot the bubbles could get before releasing their destructive energy.

However, in recent years researchers have found that temperatures inside the tiny bubbles can rise so high that the bubbles start to glow. In fact, there’s evidence that temperatures can rise as high as 15,000 Kelvin (~15,000ºC; 27,000ºF). 2 This indicates that the collapsed bubble has a hot plasma core, i.e. ‘as hot as the surface of a bright star’.3

Little wonder then that fast-flowing water can cut through solid concrete in dam tunnels—as happened at Glen Canyon Dam in 1983.4 Unexpected flood rains put such pressure on the dam’s tunnel spillways that after a few days a ‘slight rumbling and vibration’ began to be felt in the abutments and the dam itself. At that time, observers of the jets of water emerging from the tunnel portals noticed debris being forcibly ejected in the flow of water. The debris included ‘chunks of concrete, sections of rebar, and most disturbingly, what looked like pieces of sandstone, arced high above the river’.4

With no letup in the rain, Glen Canyon Dam levels rose further, and the discharge from one of the spillway tunnels ‘was turning the whole river below the dam [into] a distinct amber color.’ As one analysis of the event put it: ‘Navajo sandstone was being excavated from within the dam abutment like soil before a placer miner’s hydraulic nozzle.’4

Down in the employee dining room, located near the hydroelectric power plant at the base of the dam adjacent to the left abutment, a worker later said that it sounded like the artillery barrages he had experienced in Vietnam.

Afterwards, inspection of the worst-affected tunnel revealed a hole carved through the reinforced concrete into the sandstone. It was almost 15 metres (50 ft) deep and 45 metres (135 ft) long. A giant boulder (3 metres x 4.5 metres, or 10 ft x 15 ft) was found half-way down the tunnel (i.e. beyond the hole). The other tunnel had less severe damage, but, ‘One-inch [25-mm] rebar had been pulled out of the concrete like bones from a cooked fish.’4

The US Department of Interior later reported that it was cavitation that had started the damage, followed by dramatically increasing mechanical erosion. Interestingly, in our 1997 interview with cavitation expert Dr Edmund Holroyd, who is also a creationist, he told us of his strong belief that ‘cavitation is very important in helping us understand how massive erosion would have taken place in the early stages of the [Genesis] Flood’. Dr Holroyd was only too familiar with the potential5 destructiveness of cavitating water:

‘When water less than 10 metres deep is flowing at very high speed (say 30 metres a second) and goes over a bump, it can turn into water vapor via the formation of tiny bubbles. These collapse again when the pressure is restored, and they do so at a supersonic speed which creates shock waves with incredible pressures. This pulverizes the surface right next to where the bubbles are collapsing, so it can “eat” rock surfaces away much, much more quickly than normal erosion. In the laboratory, such cavitating water will even rapidly “eat” a steel surface.’6

Given the destructive power of rushing water, can you imagine the legacy of the global Flood? As we look around the earth’s landscape today, it’s easy to find leftover ‘signs’ of the cataclysmic inundation described in Genesis 6–9. The world is full of steep-sided gorges, canyons and ravines, eroded by the enormous floodwaters as they receded off the continents! As our knowledge of this phenomenon of cavitation grows, it surely helps us understand a little more of the massive erosion forces at work during the Flood—unless, of course, one is too ‘blind’ to see:

First of all, you must understand that in the last days scoffers will come, scoffing and following their own evil desires. … But they deliberately forget that long ago by God’s word the heavens existed and the earth was formed out of water and by water. By these waters also the world of that time was deluged and destroyed. 2 Peter 3:3–6

References

Cavitation is somewhat like boiling. Even non-boiling liquids have some molecules escaping as gas, and some of these molecules return to the liquid. At equilibrium, the gas has a certain vapour pressure. Boiling occurs when the liquid is hot enough to raise its vapour pressure above atmospheric pressure. At high altitude, it takes a lower temperature to boil because the atmospheric pressure. Cavitation takes this a step further: the fast flow of a liquid lowers the pressure by the Bernoulli effect, and when the pressure drops below the vapour pressure, bubbles of vapour are produced. Shallow water is worse because there is less pressure from the weight of the liquid. The damage is caused when the bubble bursts, since the pressure of the surrounding liquid is very high for small bubbles (inversely proportional to the radius). Return to Text.

Flannigan, D.J., and Suslick, K.S., Plasma formation and temperature measurement during single-bubble cavitation, Nature 434(7029):52–55, 3 March 2005. Return to Text.

Lohse, D., Cavitation hots up, Nature 434(7029):33–34, 3 March 2005. Return to Text.

Hannon, S., The 1983 Flood at Glen Canyon, Glen Canyon Institute, , acc. 17 October 2007. Return to Text. We do not see cavitation in every situation with fast-flowing water because conditions are not always conducive for it to occur. For example, as Dr Holroyd points out, water flowing over topographical ‘bumps’ and ‘holes’ is more likely to cavitate than water flowing over a smooth surface. Very high rates of flow are required—shallow water (< 10 metres deep) must be flowing at speeds of at least 30 m/s—and the deeper the water, the greater the speed required for cavitation. Holroyd, E., Cavitation processes during catastrophic floods, Proceedings of the 2nd International Conference on Creationism July–August 1990, pp. 101–113 (note especially pp. 108–109). Return to Text.

Cardno, S., and Wieland, C., Clouds, coins and creation: An airport encounter with professional scientist and creationist Dr Edmond Holroyd, Creation 20(1):22–23, 1997. Return to Text.


TOPICS: News/Current Events
KEYWORDS: cavitation; flood

Photo Bureau of Reclamation, U.S. Dept of the Interior

Glen Canyon Dam tunnel spillway damage in 1983

1 posted on 01/18/2012 8:39:52 AM PST by fishtank
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To: fishtank

This is a followup to this post:

http://www.freerepublic.com/focus/f-chat/2833982/posts

There were some doubts on that thread if moving water could/would rapidly erode bedrock.


2 posted on 01/18/2012 8:41:24 AM PST by fishtank (The denial of original sin is the root of liberalism.)
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To: fishtank

I’ve seen modeling of this effect used to explain features in the Scablands resulting from the ice dam breaking and abruptly draining Lake Missoula.


3 posted on 01/18/2012 8:44:53 AM PST by null and void (Day 1093 of America's ObamaVacation from reality [Heroes aren't made, Frank, they're cornered...])
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To: fishtank

More like there were cavities in the concrete from all the men who died when they fell into the concrete as it was poured! Who knows.


4 posted on 01/18/2012 8:48:25 AM PST by US_MilitaryRules (Unnngh! To many PDS people!)
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To: US_MilitaryRules

Jimmy Hoffa.

5 posted on 01/18/2012 8:52:21 AM PST by fishtank (The denial of original sin is the root of liberalism.)
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To: fishtank

Interesting.


6 posted on 01/18/2012 8:53:05 AM PST by SpaceBar
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To: logitech

ping


7 posted on 01/18/2012 8:58:12 AM PST by logitech
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To: null and void

Yep. Used to go water skiing on Lake Missoula. Tried to go fishing, but there were just suckers there.


8 posted on 01/18/2012 8:58:24 AM PST by blueunicorn6 ("A crack shot and a good dancer")
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To: US_MilitaryRules

The Glen Canyon Dam is spectacular. There is a visitors center that gives a great view of the dam and the wall of the canyon on the far side of the river.

Of interest to me was a darkened band with lots of green stuff in the canyon wall. It looked to me that the impounded water had found a course between the sandstone layers and was traveling far down stream. Plants found this water in the slickrock desert and were thriving.


9 posted on 01/18/2012 9:00:55 AM PST by bert (K.E. N.P. +12 ..... Crucifixion is coming)
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To: US_MilitaryRules

You are aware< I hope, that the stories of burials in concrete pours at Hoover and Glen Canyon are just that — stories.

They were prompted by jokers leaving boots turned upside down in fresh concrete as they left their shift. Actually in these massive placements, the concrete rises at a very slow rate due to the volume and area of the placement and the need to keep the hydraulic pressures against concrete formwork manageable. On mass pours at Hoover they talked about six inches per hour.


10 posted on 01/18/2012 9:03:00 AM PST by KC Burke
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To: fishtank
There were some doubts on that thread if moving water could/would rapidly erode bedrock.

I guess it depends on how you define "rapidly". I do know that Niagara Falls is moving slowly upriver due to bedrock erosion. (obligatory "Slowly I Turn...")

11 posted on 01/18/2012 9:11:23 AM PST by Charles Martel (Endeavor to persevere...)
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To: blueunicorn6

***... but there were just suckers there.****

OWN A MONTANA RANCH! $45,000 DOLLARS WILL GET YOU A WHOLE QUARTER ACRE! DON’T LET THIS OPPORTUNITY PASS YOU BY!


12 posted on 01/18/2012 9:38:52 AM PST by Ruy Dias de Bivar ( P!$$ on the Taliban. Issue MORE BEER!)
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To: fishtank; Alamo-Girl; betty boop
Cavitation: another straw being desperately grasped...

If the entire world is flooded (water quickly assumes equilibrium elevation), where can that water "run" to -- especially at cavitation velocities?

13 posted on 01/18/2012 9:43:53 AM PST by TXnMA ("Allah": Satan's current alias...)
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To: null and void

seems like cavitation releases a lot of energy.

Could that be harnessed to drive a turbine and produce electricity?


14 posted on 01/18/2012 9:51:46 AM PST by ckilmer
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To: ckilmer

Maybe. There was talk for a while about using cavitation to drive cold fusion. I don’t think it panned out.


15 posted on 01/18/2012 9:56:07 AM PST by null and void (Day 1093 of America's ObamaVacation from reality [Heroes aren't made, Frank, they're cornered...])
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To: TXnMA

Indeed. Thank you for sharing your insights, dear brother in Christ!


16 posted on 01/18/2012 9:56:14 AM PST by Alamo-Girl
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To: Charles Martel

Niagara Falls is realtively slow speed under little pressure compared to what they are talking about here

in the NorthWest USA there are the ‘badlands’ that look as if they had massive erosion from high pressure rushing water (only explanation that makes sense) and we are talking about state-wide flows

(global flood?)

There are deep bore holes with globe-shaped rocks inside them. these are formed by rushing water and are seen all the time, but in this case these are massive!


17 posted on 01/18/2012 9:57:30 AM PST by Mr. K (Physically unable to profreed <--- oops, see?)
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To: TXnMA

*shrug* Water would still run down from the mountains and high places until equilibrium was established.

Gotta give the YECs props on this one. At least this time they aren’t calling for the suspension of the laws of physics.


18 posted on 01/18/2012 10:00:18 AM PST by null and void (Day 1093 of America's ObamaVacation from reality [Heroes aren't made, Frank, they're cornered...])
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To: null and void

There was talk for a while about using cavitation to drive cold fusion. I don’t think it panned out.
...........
Yeah I saw that earlier. But I’m not such a physicist that I would know why you’d need a secondary effect like cold fusion to produce energy sufficient to drive a turbine...

maybe its that the energy needed to create the cavitation is greater than the energy released with cavitation—ie its endothermic.

That would be the logical reason for not trying to harvest the energy released by cavitation itself.

However, on first blush it sure doesn’t look like the net i/o is some fractional number given that the bubbles reach such high temperatures.


19 posted on 01/18/2012 10:12:56 AM PST by ckilmer
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To: Mr. K

20 posted on 01/18/2012 11:24:15 AM PST by Razzz42
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To: Mr. K

The coulees of Washington and Oregon are examples of erosion caused by enormous amount of water flowing at high speed. The Columbia River valley is one giant carve out by a draining glacial lake.


21 posted on 01/18/2012 4:45:38 PM PST by glorgau
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