1,000 Boats To Push Flood Waters From Chao Phraya River

[Crushdepth]

< snipped some math for brevity >

For days I've been reading a series of very strong opinions here re the stupidity and non workability of Plodplods' idea.

Fair enough. Those offering these opinions maybe right.

But it would be nice if the opinions could be substantiated in terms of numbers rather than interjections.

A naval screw is a fairly powerfull (reasonably efficient) pump, where does the work go?

I agree. Coincidentally, I just posed your 'where does the work go' question to GentlemanJim in a reply post. He is of the opinion that the work will end up self-canceling or disappearing or something with a 'zero, zilch, nada' effect on the river.

I'll try one last time...

Yes, there is an effect. The effect is not zero, it's just NEAR zero. It is so close to zero that it will have NO MEASURABLE IMPACT on river flow or flood levels whatsoever.

Check out the vast extent of flooded area on a satellite map. It is *laughable* to think that you could drain it to any measurable degree with bunch of boats in the river. The river is half a kilometer across, 4,000 cubic metres per second. And you're not just trying to accelerate the water going through the screws, you're trying to accelerate *all* of the water in the river downstream of the boat to the sea. It's futile. And having been down to see the navy tugs in action, I can tell you that when the TV crews aren't there the display is far less impressive. It's for show, a PR stunt for the gullible. And it annoys the hell out of me that it seems to be working.

Let me out of here...

[ResX]

< snipped some math for brevity >

For days I've been reading a series of very strong opinions here re the stupidity and non workability of Plodplods' idea.

Fair enough. Those offering these opinions maybe right.

But it would be nice if the opinions could be substantiated in terms of numbers rather than interjections.

A naval screw is a fairly powerfull (reasonably efficient) pump, where does the work go?

I agree. Coincidentally, I just posed your 'where does the work go' question to GentlemanJim in a reply post. He is of the opinion that the work will end up self-canceling or disappearing or something with a 'zero, zilch, nada' effect on the river.

A fraction of its power will heat up the body of water close to it. That not that much. The remaining fraction could end up either (1) to move the water faster or (2) it just produces surface vortex and turbulence or the combination of (1) and (2).

[MaxYakov]

Just a quick note to you number crunchers!

Most kinds of fluid flow are turbulent.

Common examples of turbulent flow are blood flow in arteries, oil transport in pipelines, lava flow, atmosphere and ocean currents, the flow through pumps and turbines, and the flow in boat wakes and around aircraft-wing tips.

In many geophysical flows (rivers, atmospheric boundary layer), the flow turbulence is dominated by the coherent structure activities and associated turbulent events. (A turbulent event is a series of turbulent fluctuations that contain more energy than the average flow turbulence ie eddies/whirlpools.)

Turbulent flows are always highly irregular. This is why turbulence problems are always treated statistically rather than deterministically.

Dig out your statistics books crunchers!

Wow! Thanks. I'll put it on the stack-of-stuff along with channel characteristics, Reynolds numbers, water temp., coriolis effect, channel flow velocity variances, tidal variations, day of week, name of the river, whether or not the PMs riverboat is doing an observation pass ... ad infinitum.

I can't even get a fix on the total KE transferred from a unknown propeller driven by a unknown engine. Not that this is a big problem. I'll just make one up, like I'd bet the Ministry of S & C would. I wonder if I'd come up with 75,000 boats (give or take)?

[longway]

A fraction of its power will heat up the body of water close to it. That not that much. The remaining fraction could end up either (1) to move the water faster or (2) it just produces surface vortex and turbulence or the combination of (1) and (2).

Fair point, that's why I stuck in the 50% efficiency, quite a bit f the power input will be wasted. Of course its not that surprising if people think it will all be wasted.

4,000 cubic metres per second.

which is 345,600,000 cubic metres a day. I got that bit right thank <snip>.

Edited October 17, 2011 by metisdead
Expletive removed.

[ResX]

Just a quick note to you number crunchers!

Most kinds of fluid flow are turbulent.

Common examples of turbulent flow are blood flow in arteries, oil transport in pipelines, lava flow, atmosphere and ocean currents, the flow through pumps and turbines, and the flow in boat wakes and around aircraft-wing tips.

In many geophysical flows (rivers, atmospheric boundary layer), the flow turbulence is dominated by the coherent structure activities and associated turbulent events. (A turbulent event is a series of turbulent fluctuations that contain more energy than the average flow turbulence ie eddies/whirlpools.)

Turbulent flows are always highly irregular. This is why turbulence problems are always treated statistically rather than deterministically.

Dig out your statistics books crunchers!

Wow! Thanks. I'll put it on the stack-of-stuff along with channel characteristics, Reynolds numbers, water temp., coriolis effect, channel flow velocity variances, tidal variations, day of week, name of the river, whether or not the PMs riverboat is doing an observation pass ... ad infinitum.

I can't even get a fix on the total KE transferred from a unknown propeller driven by a unknown engine. Not that this is a big problem. I'll just make one up, like I'd bet the Ministry of S & C would. I wonder if I'd come up with 75,000 boats (give or take)?

You don't need turbulence model for this kind of problem. Without turbulence model you are going to compromise the accuracy of the calculation. It will not going to change to final value that you want to use as the basis of your decision. Bernoulli continuity equation for steady state incompressible flow will able to give the conclusion that you want. That is the simplest of fluid dynamic, It cannot simpler.

[bobo42]

... What happens to a very small amount of water that you throw into the river at 20 knots? The same thing happens, the water ends up moving on its own and encounters the massive resistance of hundreds of millions of M3 of water, that is NOT moving at 20 knots. End result, they reach equilibrium and the net overall change in speed of the larger volume of water is zero, zilch, nada. ...

This is completely incorrect. Please review the first law of thermodynamics.

If I dip a paddle in the Chao Phraya and swish it toward the sea, I have added energy to its flow by an extremely infinitesimal - but non-zero - amount, this is different than "zero, zilch, nada". The energy imparted to that water does not magically disappear just because it interacts with other water, no matter how many millions of cubic meters. No matter how complex the modeling you may use, you will never come up with zero additional energy, except by rounding down.

The discussion here is an interesting exercise in simple physics, nothing more. Of course most of us know that the additional energy added by a few thousand boats will still be quite infinitesimal as compared to the energy of the massive volume of water in the river, this however is no reason to ignore the most basic laws of physics.

[MaxYakov]

< snipped some math for brevity >

For days I've been reading a series of very strong opinions here re the stupidity and non workability of Plodplods' idea.

Fair enough. Those offering these opinions maybe right.

But it would be nice if the opinions could be substantiated in terms of numbers rather than interjections.

A naval screw is a fairly powerfull (reasonably efficient) pump, where does the work go?

I agree. Coincidentally, I just posed your 'where does the work go' question to GentlemanJim in a reply post. He is of the opinion that the work will end up self-canceling or disappearing or something with a 'zero, zilch, nada' effect on the river.

A fraction of its power will heat up the body of water close to it. That not that much. The remaining fraction could end up either (1) to move the water faster or (2) it just produces surface vortex and turbulence or the combination of (1) and (2).

Thanks, ResX. I'd would think (hope?) it's a combination of relatively downstream velocity and turbulence. Any idea at all on the percentage of heat/turbulance losses or how to determine it? How about sub-surface vortexes? I believe the prop wash is rotating about the prop shaft axis. Important factors that would materially decrease the efficiency of this ... ahem ... science experiment.

You know, what just struck me about this is that this (obviously!) is not the intended or ideal use of a boat's propulsion system. I know this sounds naive, but these issues of turbulence and increasing water velocity are not the main concern of a boat designer or operator. Submarine propulsion system designers are concerned about noise (cavitation) and efficiency of propulsion must be an issue in most boat designs. The design is primarily to optimize the propulsion of the boat, not to optimize the propulsion of the water in which it's sitting (unless that also is to optimize the boat's movement through the water). What happens far downstream from the props must not be that big a concern as it is in this twisted use of boat propulsion as water pumps. And, considering the turbulence issue, probably very inefficient ones for this purpose.

[ResX]

Just a quick note to you number crunchers!

Most kinds of fluid flow are turbulent.

Common examples of turbulent flow are blood flow in arteries, oil transport in pipelines, lava flow, atmosphere and ocean currents, the flow through pumps and turbines, and the flow in boat wakes and around aircraft-wing tips.

In many geophysical flows (rivers, atmospheric boundary layer), the flow turbulence is dominated by the coherent structure activities and associated turbulent events. (A turbulent event is a series of turbulent fluctuations that contain more energy than the average flow turbulence ie eddies/whirlpools.)

Turbulent flows are always highly irregular. This is why turbulence problems are always treated statistically rather than deterministically.

Dig out your statistics books crunchers!

Wow! Thanks. I'll put it on the stack-of-stuff along with channel characteristics, Reynolds numbers, water temp., coriolis effect, channel flow velocity variances, tidal variations, day of week, name of the river, whether or not the PMs riverboat is doing an observation pass ... ad infinitum.

I can't even get a fix on the total KE transferred from a unknown propeller driven by a unknown engine. Not that this is a big problem. I'll just make one up, like I'd bet the Ministry of S & C would. I wonder if I'd come up with 75,000 boats (give or take)?

That's won't be that difficult. In this case you have to calculate KE based on rate form: Here is the formula

KE (J/s) = 0.5 X( mass or water/s) X water velocity ^2.

Do it twice. The first one by assuming its initial velocity. Then the new velocity. The diff of two will give you additional realized power(W) that you have to put in in order to bring the speed of water faster. The actual power you have to divide your answer with conversion efficiency of the sources. Don't forget to multiply volumetric flow rate with water density to get mass flow.

But this is not all about the issue we are discussing.

[ResX]

... What happens to a very small amount of water that you throw into the river at 20 knots? The same thing happens, the water ends up moving on its own and encounters the massive resistance of hundreds of millions of M3 of water, that is NOT moving at 20 knots. End result, they reach equilibrium and the net overall change in speed of the larger volume of water is zero, zilch, nada. ...

This is completely incorrect. Please review the first law of thermodynamics.

If I dip a paddle in the Chao Phraya and swish it toward the sea, I have added energy to its flow by an extremely infinitesimal - but non-zero - amount, this is different than "zero, zilch, nada". The energy imparted to that water does not magically disappear just because it interacts with other water, no matter how many millions of cubic meters. No matter how complex the modeling you may use, you will never come up with zero additional energy, except by rounding down.

The discussion here is an interesting exercise in simple physics, nothing more. Of course most of us know that the additional energy added by a few thousand boats will still be quite infinitesimal as compared to the energy of the massive volume of water in the river, this however is no reason to ignore the most basic laws of physics.

Many posters over estimate the amount of energy associated with water that flows at the rate of 4,000,0000kg/s (4,000m3/s). No it is NOT big at all. Use kinetic energy formula for water velocity 2m/s: KE (J/s) =0.5 *4 X 10^6 * 2*2=8.0MW. Surprisingly that huge amount of water that travels at 2m/s will not able to power a 8MW a hydro turbine generator. An average speed boat has a capacity of close to 0.1MW. It takes the power of 100 speed boats to move 4,000,000kg/s of water at 2m/s assuming 100% efficiency.

[MaxYakov]

I'll try one last time...

< snipped to below >

Let me out of here...

Yes, there is an effect. The effect is not zero, it's just NEAR zero. It is so close to zero that it will have NO MEASURABLE IMPACT on river flow or flood levels whatsoever.

We're trying to get a feel for how NEAR zero and why using some crude metrics. I saw nothing indicating 'flood levels' would be impacted. Are you referring to flood level outside the river banks? Because if you are, I don't see how they would be impacted with or without boats pumping water on Chao Phraya.

Check out the vast extent of flooded area on a satellite map. It is *laughable* to think that you could drain it to any measurable degree with bunch of boats in the river. The river is half a kilometer across, 4,000 cubic metres per second. And you're not just trying to accelerate the water going through the screws, you're trying to accelerate *all* of the water in the river downstream of the boat to the sea.

I don't any believe anyone here, or at the Ministry of S & C thought this 'experiment' would drain ANYTHING. That doesn't seem to be the intent. The intent appears to be to increase the speed of water flow in the river to the Bay. Yes, trying to accelerate some, maybe all, of the river by some probably immeasurable amount.

It's futile. And having been down to see the navy tugs in action, I can tell you that when the TV crews aren't there the display is far less impressive. It's for show, a PR stunt for the gullible. And it annoys the hell out of me that it seems to be working.

What do they do when the TV crews aren't there?

My main thrust, besides that's it's a passably interesting Physics problem, is to get some metrics on it to determine at what level (if any) of boat use would this cease to be simply a PR stunt. A number of 75,000 boats has recently been allegedly mentioned, from the Minister. Metrics should be applied to that and any other number of boats, or scenario. It looks to me that if he's saying now that he needs that number, then this much smaller number of boats thrashing the river could be seen as negligent of him. Sort of like trying to build a runway with a garden spade or paint a building with a tooth brush, you think?

What do you think? Does it matter how many boats there are in this 'experiment'? Assume that these are not insignificant boats. Ignore fuel efficiency, because I'm sure we all have the feeling that this has to be the most inefficient operation on water that has ever been conceived.

If nothing else, I agree with your 'Let me out of here'.

[GentlemanJim]

<br>

<br>... What happens to a very small amount of water that you throw into the river at 20 knots? The same thing happens, the water ends up moving on its own and encounters the massive resistance of hundreds of millions of M3 of water, that is NOT moving at 20 knots. End result, they reach equilibrium and the net overall change in speed of the larger volume of water is zero, zilch, nada. ...<br><br>

<br><br>This is completely incorrect. Please review the first law of thermodynamics. <br><br>If I dip a paddle in the Chao Phraya and swish it toward the sea, I have added energy to its flow by an extremely infinitesimal - but non-zero - amount, this is different than "zero, zilch, nada". The energy imparted to that water does not magically disappear just because it interacts with other water, no matter how many millions of cubic meters. No matter how complex the modeling you may use, you will never come up with zero additional energy, except by rounding down.<br><br>The discussion here is an interesting exercise in simple physics, nothing more. Of course most of us know that the additional energy added by a few thousand boats will still be quite infinitesimal as compared to the energy of the massive volume of water in the river, this however is no reason to ignore the most basic laws of physics.<br>

<br><br>Why is this soooo bloody difficult? I am totally uninterested in starting to consider where the KE is transferred to. This whole exercise in futility started because of the Governments more than silly attempt to make a change to floodwaters by using boats to accelerate the water out to sea. The discussion is NOT an interesting exercise in simple physics because some of you are being too simplistic to make it the remotest bit interesting. What this is all about is can the boats make a difference on the <b>physica</b>l water levels in the river, a difference that everyone will see because the water goes away. The answer is NO! Regardless of any calculations and obsessions with basic laws of physics, the practical answer if you are stood at the end of the river with measuring equipment is it will not make a blind jot of difference. So in <b>practical terms </b>we can say that the result was zero, zilch, nada. Is that crystal clear? I am not interested in what you come up with that may show a millionth or billionth of a knot difference, I am interested in the claims by the government that 'this will help solve the flooding'. And it doesn't! It made NO difference. If I could stand there and physically measure the difference the boats make, I would eat my shorts.<br><br>So, is my meaning clear? Zero, Zilch, Nada!

<div><br></div><div>Imagine this as a little like the schoolboy idea of 'if all the chinamen jumped up and down at the same time would you move the earth"? Well would you? All that kinetic energy has to go somewhere! Will it make one iota difference to our interplanetary movements? ..No! Now the thread is essentially about using boats to stop the flooding. If you want a discussion on theoretical physics problems there are a whole load of forums out there just for you.</div>

Edited October 17, 2011 by GentlemanJim

[ResX]

Honestly speaking I don't know the way it is done makes significant impact. But I know for sure the approach can influence limited stretch from the sea. To give an example, such operation will not make the water inside Bhumibol reservoir to move faster. This is only an analogy. Certain areas that are flooding right now along the natural river path may also cannot be influenced by by this approach. The area of influenced is limited to a point that the water at that point "sees" the change in water level at the downstream. In layman term, the water has its "own way" to transmit information. The "information" at any point cannot travel through any stretch that has zero potential energy (e.g. water fall). That for sure. So the speed of water on the top of waterfall and higher cannot be altered by this approach. This is only one of the examples.

[GentlemanJim]

[ResX]

Let us perform an experiment. Let us fill up the Bumibol dam up to Elevation says 200m from sea level. Its volume at this level is says 12.5billion cubic meter. Just after we get its elevation exactly at 200.0000m from sea level we close all the discharge gates. Next, we divert incoming flows from its tributaries to else where. Therefore no water is coming in and no water is moving out. Then, we measure accurately a few elevations of the water surface it creates accurat up to 4 decimal place from sea level. Two of the important points to be measured are the furthest distance from its intake structure and just above its intake structure. This intake structure is the closest point to the discharge gate. Do you think that we cannot get similar readings up to 3 decimal place? They have to be similar. If no disturbance the water is very efficient to maintain its level constant level every where.

Now let us run a hydro turbine generator. We discharge 40m3/s. We measure again those two points. The furthest point and the closest point to the discharge gate. Do you think the readings for these two points will be the same up to 3 decimal place? If you think they are the same then you have to find the answer how the water from the furthest point travels to the discharge. Remember, the only force that you have here is gravitational force. But gravity will not pull anything horizontally. Think about it or accept this explanation. When we open the discharge gate the water will flow out by gravity. This causes the water just near the intake losses its potential energy. Therefore its water level is slightly lower when compared to the furthest point. The entire Bhumibol reservoir in fact is inclined at the angle of say 2cm vertical downward for every 150km horizontal by assuming the average lenght of the reservoir is 150km. This angle of inclination and gravitational acceleration that transports water from every corner of the reservoir. The lowest level will be the area close to the discharge gate. If we increase the discharge, the angle of inclination will increase. The water will move faster.

Actually you can observe this fact when you start up a hydro turbine generator. The water level above its intake will go down a few cm. Even volume of water inside Bhumibol dam is such a huge amount , but we still can measure the angle of inclination because of we increase water velocity. We also can calculate the average velocity of water inside the reservoir.

Basically what the 1000boats wish to achieve is similar to our experiment above. The flood has transformed vast area into an unwanted reservoir. Except of one thing. In our case we can hold water velocity near outlet a constant. Can that 1000 boats do the same?

Edited October 17, 2011 by ResX

[BabySun]

Water Drainage by Boats to Continue until Month's End

Officials expect that the strategy of using boats' propellers to accelerate the drainage of water out to the sea will be required through the end of October due to runoffs from the North and rain, which will continue to cause water levels to rise.

-- Tan Network 2011-10-17

@MaxYakov

The dogs bark but the caravan moves on

[Buchholz]

Water Drainage by Boats to Continue until Month's End

Officials expect that the strategy of using boats' propellers to accelerate the drainage of water out to the sea will be required through the end of October due to runoffs from the North and rain, which will continue to cause water levels to rise.

-- Tan Network 2011-10-17

@MaxYakov

The dogs bark but the caravan moves on

Perhaps we can begin a new science and mathematics discussion.

How many barrels of diesel fuel will 75,000 ships consume if they run 24 hours a day for 2 weeks?

.

[ResX]

A fraction of its power will heat up the body of water close to it. That not that much. The remaining fraction could end up either (1) to move the water faster or (2) it just produces surface vortex and turbulence or the combination of (1) and (2).

Fair point, that's why I stuck in the 50% efficiency, quite a bit f the power input will be wasted. Of course its not that surprising if people think it will all be wasted.

4,000 cubic metres per second.

which is 345,600,000 cubic metres a day. I got that bit right thank <snip>.

The net power transfer from the propellers to water is expected to be far lower than 50%. It must be less than 15% based on my intellectual guess. You see. It can't be more efficient than a diesel engine used by an ordinary car since the drag resistance water is much higher air. An ordinary diesel engine fora car has the maximum efficiency around 30%. So I think below 15% is reasonable. Anyway, I don't think cost & efficiency are the main issue of the debate. The main issue is whether it will give significant impact or not.

[MaxYakov]

Water Drainage by Boats to Continue until Month's End

Officials expect that the strategy of using boats' propellers to accelerate the drainage of water out to the sea will be required through the end of October due to runoffs from the North and rain, which will continue to cause water levels to rise.

-- Tan Network 2011-10-17

@MaxYakov

The dogs bark but the caravan moves on

Perhaps we can begin a new science and mathematics discussion.

How many barrels of diesel fuel will 75,000 ships consume if they run 24 hours a day for 2 weeks?

.

The quick, science and math answer straight from the Ministry of S & T: A Lot

How about this one?:

How many posts/day would you have to do between now and Nov 1st to raise your 17-month average to 14 posts per/day?

Edited October 18, 2011 by MaxYakov

[longway]

^^ There was an article in a popular english language newspaper stating that are hoping for 50 million cubic m extra per day with 1,100 boats (500 on the chao prhaya, the rest split between the Bang Prakong and Tha Chin), it doesn't sound like enough to make much difference.

Going by your 15% efficiency and having 1,100 boats means that each boat has to average 127 HP (with 15% of that figure going into pushing water) 24 hours a day to achieve the figure stated. Tugs can have 2,000 or more HP engines, but there cannot be many places where they can be moored safely and effectively put out such huge power, then you would also have overflow concerns further down stream anyway.

It just surprises me that the power requirements though large, are not as astronomical in the way I would have first assumed. Though the costs of an operation such as this may well be.

Edited October 18, 2011 by longway

[MaxYakov]

^^ There was an article in a popular english language newspaper stating that are hoping for 50 million cubic m extra per day with 1,100 boats (500 on the chao prhaya, the rest split between the Bang Prakong and Tha Chin), it doesn't sound like enough to make much difference.

Going by your 15% efficiency and having 1,100 boats means that each boat has to average 127 HP (with 15% of that figure going into pushing water) 24 hours a day to achieve the figure stated. Tugs can have 2,000 or more HP engines, but there cannot be many places where they can be moored safely and effectively put out such huge power, then you would also have overflow concerns further down stream anyway.

It just surprises me that the power requirements though large, are not as astronomical in the way I would have first assumed.

1) If you use the 1,100 number, then remember that any effect occurs among the three rivers.

2) A good point with the 'cannot be many places where the cannot be moored safely'. Many of the boats are now being tied abreast (apparently to a common mooring point). And 'safety' may have multiple definitions here - TiT

3) With only 15% going into pushing water? Before, you were using 50%. Or do you mean 85% efficiency, instead? It makes a BIG difference, of course.

4) Downstream increase in water level? Do you think it would really be material? Take the 50M m³/day and spread it both over both the surface area of the river(s) and over time to see what the vertical increase would be. This is assuming that increasing the velocity of the water really can/does raise the river level. Remember that using the 1,100 boat figure is involves all three rivers and each river probably has it's own, unique flow characteristics.

5) Should we let Buchholz work on the fuel consumption values? :jap:

Thanks Much

Edited October 18, 2011 by MaxYakov

[longway]

^ Not just the costs, its likely a logistical nightmare, bunkering so many vessels.

[MaxYakov]

^ Not just the costs, its likely a logistical nightmare, bunkering so many vessels.

Not to mention that such diesel consumption could threaten the government's allocation of same for flood control. I'm being so nice this morning - didn't even mention SUVs and MBZs.

[Buchholz]

Water Drainage by Boats to Continue until Month's End

Officials expect that the strategy of using boats' propellers to accelerate the drainage of water out to the sea will be required through the end of October due to runoffs from the North and rain, which will continue to cause water levels to rise.

-- Tan Network 2011-10-17

@MaxYakov

The dogs bark but the caravan moves on

Perhaps we can begin a new science and mathematics discussion.

How many barrels of diesel fuel will 75,000 ships consume if they run 24 hours a day for 2 weeks?

.

The quick, science and math answer straight from the Ministry of S & T: A Lot

How about this one?:

< a repeat of the same trolling nonsense comments that were moderator-deleted yesterday are snipped today >

Agreed. It's going to be to a lot.

p.s. if mods delete your stuff, it's best not to repeat it again.

[peterdk]

I for one, would just love to see the maths behind it, posted in a news source, so we can see why they started this exercise in the first place.

You would assume, that they had some scientists working behind the scenes, coming up with a formula, that showed how much it would help.

As said earlier, if someone got the idea to make all the Chinese jump at the same time - would it move the Earth ?

Futile and PR, unless some serious math is behind it, backing up the decision.

Is it safe to assume, that there is such math behind this exercise ?

[hyperdimension]

The river is half a kilometer across

It's almost 2km wide near the estuary.

[hyperdimension]

Science and Technology Minister Plodprasop Suraswadi said that on the Chao Phraya River in Nonthaburi, about 500 boats are taking part in the operation from Phra Nangklao Bridge to the estuary, another 300 boats will work on the Bangprakong River and the other 300 boats in the Tha Chin River.

"from Phra Nangklao Bridge to the estuary" is a long way with many twists and turns. Here's a link to Google Maps centred on Pranangklao hospital, a little south of the bridge: Pranangklao hospital. Zoom out to see how far it is to the estuary.

[MaxYakov]

I for one, would just love to see the maths behind it, posted in a news source, so we can see why they started this exercise in the first place.

You would assume, that they had some scientists working behind the scenes, coming up with a formula, that showed how much it would help.

As said earlier, if someone got the idea to make all the Chinese jump at the same time - would it move the Earth ?

Futile and PR, unless some serious math is behind it, backing up the decision.

Is it safe to assume, that there is such math behind this exercise ?

I would assume that they would have nobody (behind the scenes or otherwise) 'coming up with a formula' because it would might prove its effectiveness and inefficiency. The 'water diversion' deniers at M of S & T who might be doing the math independently would be suppressed, IMHO.

That someone (name withheld to protect the guilty) who made the the 'all the Chinese jump' comparison did so in a paragraph that was laced with similar, Straw Man arguments as well as risked being accused of being a bigot, if not worse IMHO.

Won't find any serious math here (just us amateurs) ... or over at the M of S & T, either, I'd bet.

Edited October 18, 2011 by MaxYakov

[BabySun]

I for one, would just love to see the maths behind it, posted in a news source, so we can see why they started this exercise in the first place.

You would assume, that they had some scientists working behind the scenes, coming up with a formula, that showed how much it would help.

As said earlier, if someone got the idea to make all the Chinese jump at the same time - would it move the Earth ?

Futile and PR, unless some serious math is behind it, backing up the decision.

Is it safe to assume, that there is such math behind this exercise ?

Poster ResX is water engineer and he knows his stuff.read his posts - you will understand everything,the rest of boys here struggle with grammar/high school.

[cloudhopper]

Let us perform an experiment. Let us fill up the Bumibol dam up to Elevation says 200m from sea level. Its volume at this level is says 12.5billion cubic meter. Just after we get its elevation exactly at 200.0000m from sea level we close all the discharge gates. Next, we divert incoming flows from its tributaries to else where. Therefore no water is coming in and no water is moving out. Then, we measure accurately a few elevations of the water surface it creates accurat up to 4 decimal place from sea level. Two of the important points to be measured are the furthest distance from its intake structure and just above its intake structure. This intake structure is the closest point to the discharge gate. Do you think that we cannot get similar readings up to 3 decimal place? They have to be similar. If no disturbance the water is very efficient to maintain its level constant level every where.

Now let us run a hydro turbine generator. We discharge 40m3/s. We measure again those two points. The furthest point and the closest point to the discharge gate. Do you think the readings for these two points will be the same up to 3 decimal place? If you think they are the same then you have to find the answer how the water from the furthest point travels to the discharge. Remember, the only force that you have here is gravitational force. But gravity will not pull anything horizontally. Think about it or accept this explanation. When we open the discharge gate the water will flow out by gravity. This causes the water just near the intake losses its potential energy. Therefore its water level is slightly lower when compared to the furthest point. The entire Bhumibol reservoir in fact is inclined at the angle of say 2cm vertical downward for every 150km horizontal by assuming the average lenght of the reservoir is 150km. This angle of inclination and gravitational acceleration that transports water from every corner of the reservoir. The lowest level will be the area close to the discharge gate. If we increase the discharge, the angle of inclination will increase. The water will move faster.

Actually you can observe this fact when you start up a hydro turbine generator. The water level above its intake will go down a few cm. Even volume of water inside Bhumibol dam is such a huge amount , but we still can measure the angle of inclination because of we increase water velocity. We also can calculate the average velocity of water inside the reservoir.

Basically what the 1000boats wish to achieve is similar to our experiment above. The flood has transformed vast area into an unwanted reservoir. Except of one thing. In our case we can hold water velocity near outlet a constant. Can that 1000 boats do the same?

Nice analogy. The total carrying capacity (widthXdepth) of the river is the same as your turbine outlets since that is the rate limiting feature controlling the outflow. Now do you think that if we placed any number of boats along the surface of your tilted reservoir/river we could in any way influence how fast the reservoir drained through a given outlet opening?

Clearly not.

Edited October 18, 2011 by cloudhopper

[MaxYakov]

I for one, would just love to see the maths behind it, posted in a news source, so we can see why they started this exercise in the first place.

You would assume, that they had some scientists working behind the scenes, coming up with a formula, that showed how much it would help.

As said earlier, if someone got the idea to make all the Chinese jump at the same time - would it move the Earth ?

Futile and PR, unless some serious math is behind it, backing up the decision.

Is it safe to assume, that there is such math behind this exercise ?

Poster ResX is water engineer and he knows his stuff.read his posts - you will understand everything,the rest of boys here struggle with grammar/high school.

I'll take your blessing of ResX's expertise as good advisement, Thanks.

Are we to take it that 'the rest of boys here' struggling with 'grammar/high school' is self-inclusive?

Edited October 18, 2011 by MaxYakov