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

[hyperdimension]

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

There has probably been more mathematics done by some here on this experiment than at the Ministry of Science and Technology.

[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?

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.

You are right. The answer is no. That is not the situation we are looking for. If we can "put" a boat inside the discharge tunnel and its propeller provides thrust in the direction of flow, holding the gate opening to be the same, what do you think? Do you think that its flow rate will increase higher than 40m3/s?

If you put the boat after the pressurized tunnel (Tail race pond) it won't work either. There is another law of physics that tells you it won't work. The last location you can put the "boat" just before the water leaving the pressurized tunnel. To be honest, this scenario is the closest scenario that I can think of and it is quite easy to understand. In the case of 1000boats, no, it may not be exactly similar.

[ResX]

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.

Thank you. You are right I'm. I mean about water engineer. I think I understand the subject I wish to share. Not everything.

[longway]

^ 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.

In case anyone is even remotely interested I found this page.

Fuel consumption by HP

Your engine uses the fuel you purchase in several ways.

35 percent is given up to the atmosphere in heat

25 percent is given up in heat and vibration absorbed by surrounding water

10 percent is given up to overcome wave resistance

6 percent to overcome wave formation and prop wash against the hull

7 percent to overcome skin friction

2 percent is wasted in friction at the propeller shaft

1 percent to overcome air resistance

This leaves about 13-14 percent of the original energy to turn the propeller.

How much do gasoline and diesel engines consume?

Diesel engines consume about 1 gallon per hour for every 18 hp used. You can estimate the number of gallons consumed per hour by multiplying horsepower used by 0.055.

Gasoline four stroke inboard engines need about 1 gallon per hour for every 10 hp used. The number of gallons consumed per hour can be estimated by multiplying horsepower used by 0.100. (see note above)

Outboards might use considerably more since two stroke motors seem to have a greater thirst than four stroke motors.

Rounding up the 13-14% to 15%, then each of the 1,100 boats has to have average about 127 HP to get the 50 million cube extra discharge.

Using the most conservative fuel consumption estimate: 127/18 x 4 (gallons to litres) = 28 litres per hour per boat.

So per day costs; 28 l x 1100 boats x 24 hours x 35B equals about 26 million baht per day minimum on fuel alone.

Even if you double this figure its not too high in relative terms, being about 1 million pounds sterling a day.

The higher ups in this government probably spend about the same in gucci handbgags, gold leaf facials, pedicures, expensive luncheons and 1st class flights to dubai to help them get through the stress of the flooding anyway.

I still dont know if its a stupid idea or not, but there seems to be enough substance for me to go from to

[Crushdepth]

... 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.

You may be having an interesting theoretical physics discussion, but the OP is about the merits of this exercise in relation to flood mitigation. Whether the effect is precisely zero or so near zero that nobody can tell the difference is irrelevant. In practical terms it is a complete waste of time and resources that could have been spent on real relief.

[hyperdimension]

So per day costs; 28 l x 1100 boats x 24 hours x 35B equals about 26 million baht per day minimum on fuel alone.

Could there have been a deal worked out with PTT or some other fuel provider, in which someone gets a nice cut of profits, before they went ahead with this?

Does anyone know the details of how Plodprasop became so rich?

[Thaddeus]

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

There has probably been more mathematics done by some here on this experiment than at the Ministry of Science and Technology.

I say someone should forward this thread to The Discovery Channel and let the Myth Busters have a go at it.

And get it over-dubbed in Thai.

[Buchholz]

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?

Using the most conservative fuel consumption estimate: 127/18 x 4 (gallons to litres) = 28 litres per hour per boat.

Thanks.

28 x 24 (hours) x 14 (days) x 75,000 (boats) = 705,600,000 liters of diesel x 28 Baht (per liter) = 19,756,800,000 Baht

705,600,000 liters / 159 (per barrel) = 4,437,735 Barrels of Diesel

Well done, Plodprasop. Let's see it through.

.

[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.

You may be having an interesting theoretical physics discussion, but the OP is about the merits of this exercise in relation to flood mitigation. Whether the effect is precisely zero or so near zero that nobody can tell the difference is irrelevant. In practical terms it is a complete waste of time and resources that could have been spent on real relief.

Just to provide the info that many posters were looking for. The short answer to you question is I don't know. Scientific fundamental is one aspect of it. Procedure is the other aspect. Site conditions, etc. But the persons who currently carry out the task shall know the answer less than 1hour after the started. If they don't publish the result then you just assume it doesn't work.

[MaxYakov]

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?

Using the most conservative fuel consumption estimate: 127/18 x 4 (gallons to litres) = 28 litres per hour per boat.

Thanks.

28 x 24 (hours) x 14 (days) x 75,000 (boats) = 705,600,000 liters of diesel x 28 Baht (per liter) = 19,756,800,000 Baht

705,600,000 liters / 159 (per barrel) = 4,437,735 Barrels of Diesel

Well done, Plodprasop. Let's see it through.

.

i didn't even check the math beyond the 75 x 10³ boats. Why, you ask? Because Minister Surasawadi doesn't have them AND will never have them.

Instead of running a local CJ just to make a cheap swipe at the Minister, why doesn't one of you apply longway's fuel consumption/engine sizes from his recent guesstimate to do something that could at least resemble something useful?

While you're at it, it would be nice if you'd brush up on your scientific notation. All these zeros are starting to remind me how 'zero, zilch, nada' this effort probably is. :jap:

[cloudhopper]

You are right. The answer is no. That is not the situation we are looking for. If we can "put" a boat inside the discharge tunnel and its propeller provides thrust in the direction of flow, holding the gate opening to be the same, what do you think? Do you think that its flow rate will increase higher than 40m3/s?

If you put the boat after the pressurized tunnel (Tail race pond) it won't work either. There is another law of physics that tells you it won't work. The last location you can put the "boat" just before the water leaving the pressurized tunnel. To be honest, this scenario is the closest scenario that I can think of and it is quite easy to understand. In the case of 1000boats, no, it may not be exactly similar.

I don't think that is a valid analogy because a river is not a tube, pipe or tunnel and cannot be pressurized. It seems to me that the total flow is determined entirely by the gravity gradient and the geologic features of the river bed and accelerating a local volume within it cannot change the overall flow rate (which is always at the maximum for a given volume unless obstructed by e.g. large moored vessels).

[Buchholz]

Thanks.

28 x 24 (hours) x 14 (days) x 75,000 (boats) = 705,600,000 liters of diesel x 28 Baht (per liter) = 19,756,800,000 Baht

705,600,000 liters / 159 (per barrel) = 4,437,735 Barrels of Diesel

Well done, Plodprasop. Let's see it through.

i didn't even check the math beyond the 75 x 10³ boats. Why, you ask? Because Minister Surasawadi doesn't have them AND will never have them.

Why never? Plodprasop is a man of action.

He said 1,000 earlier and, by God, he got a 1,000.

Now he's saying 75,000 should be quickly provided, so you shouldn't discount what he's capable of.

Instead of running a local CJ just to make a cheap swipe at the Minister, why doesn't one of you apply longway's fuel consumption/engine sizes from his recent guesstimate to do something that could at least resemble something useful?

19.7 Billion Baht ain't cheap and what could more useful than determining what Plodprasop's plan will cost and how much fuel is involved in his latest intention?

It seems more relevant than some inconsequential movement of flood waters.

.

[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.

In case anyone is even remotely interested I found this page.

Fuel consumption by HP

Your engine uses the fuel you purchase in several ways.

35 percent is given up to the atmosphere in heat

25 percent is given up in heat and vibration absorbed by surrounding water

10 percent is given up to overcome wave resistance

6 percent to overcome wave formation and prop wash against the hull

7 percent to overcome skin friction

2 percent is wasted in friction at the propeller shaft

1 percent to overcome air resistance

This leaves about 13-14 percent of the original energy to turn the propeller.

How much do gasoline and diesel engines consume?

Diesel engines consume about 1 gallon per hour for every 18 hp used. You can estimate the number of gallons consumed per hour by multiplying horsepower used by 0.055.

Gasoline four stroke inboard engines need about 1 gallon per hour for every 10 hp used. The number of gallons consumed per hour can be estimated by multiplying horsepower used by 0.100. (see note above)

Outboards might use considerably more since two stroke motors seem to have a greater thirst than four stroke motors.

Rounding up the 13-14% to 15%, then each of the 1,100 boats has to have average about 127 HP to get the 50 million cube extra discharge.

Using the most conservative fuel consumption estimate: 127/18 x 4 (gallons to litres) = 28 litres per hour per boat.

So per day costs; 28 l x 1100 boats x 24 hours x 35B equals about 26 million baht per day minimum on fuel alone.

Even if you double this figure its not too high in relative terms, being about 1 million pounds sterling a day.

The higher ups in this government probably spend about the same in gucci handbgags, gold leaf facials, pedicures, expensive luncheons and 1st class flights to dubai to help them get through the stress of the flooding anyway.

I still dont know if its a stupid idea or not, but there seems to be enough substance for me to go from to

Thanks, again longway. I had missed this post when I was replying to Buchholz's post. This is what I was looking for. I believe there are some adjustments in order, I believe because the boats are moored:

35 percent is given up to the atmosphere in heat

- To the water, mostly, in this case - Unintended Consequence

25 percent is given up in heat and vibration absorbed by surrounding water

- Losses to heat again?

10 percent is given up to overcome wave resistance

- Does not apply to the case of a moored vessel

6 percent to overcome wave formation and prop wash against the hull

- Overcome wave formation doesn't apply, prop wash against hull?

7 percent to overcome skin friction

- Does not apply

2 percent is wasted in friction at the propeller shaft

- Maybe the Minister can find a way to do his experiment without turning the screws?

1 percent to overcome air resistance

- Does not apply

This leaves about 13-14 percent of the original energy to turn the propeller.

Rough, adjusted efficiency estimate based on the fact that the boats are moored:

100% - (35% (heat) +25% (more heat/vibes) +1% (hull prop wash - arguable) +2% (prop shaft)) = 37%

I'm wondering about the 40% total loss between both atmospheric, water jacket and vibration.

Thanks Again for the research and effort.

[cloudhopper]

That is not the situation we are looking for. If we can "put" a boat inside the discharge tunnel and its propeller provides thrust in the direction of flow, holding the gate opening to be the same, what do you think? Do you think that its flow rate will increase higher than 40m3/s?

Sorry for the temerity to debate a hydrologist but one more experiment.

Let's put a huge diameter pipe along the bottom of the river for 20 meters with a powerful pump inside. I concede that the water level at the upstream intake end will lower and the "tilt" of the river will steepen upstream, increasing the flow. However at the output end of our pump we find that we have increased the river level by an identical amount which flows away equally in all directions, with a slight bias toward downstream. However this is all immediately negated by the newly-formed upstream gradient we create as the humped water at the outlet now has an even steeper and far shorter gravity gradient to follow back upstream into the hole we created at the intake end. Result - localized circular flow in an open system with zero effect on the overall system flow..

[BabySun]

@peterdk

here is something for you - from the very beginning of this thread;after you are through it - tell us,what you will learn?This is post#21,you have to go there to download pdf.

Just in case somebody is bored on this lovely Saturday evening.

"Flow Dynamics in Open Channels and Rivers"

[Buchholz]

So per day costs; 28 l x 1100 boats x 24 hours x 35B equals about 26 million baht per day minimum on fuel alone.

Could there have been a deal worked out with PTT or some other fuel provider, in which someone gets a nice cut of profits, before they went ahead with this?

Does anyone know the details of how Plodprasop became so rich?

The wealthiest Cabinet minister is Science and Technology Minister Plodprasop Suraswadi with declared net assets of 963.5 Million Baht. Plodprasop has spent much of his career in government service in areas related to natural resources, including as director of the fisheries and forestry departments.

Associated Press

http://gulftoday.ae/portal/079ed919-f8eb-4c1e-8586-3330d3cf4910.aspx

[cdnvic]

Bringing any member of the Royal Family, even by hinting, into an argument can get you banned permanently. Use your heads before posting please.

[cloudhopper]

Does anyone know the details of how Plodprasop became so rich?

Plodprasop has spent much of his career in government service in areas related to natural resources, including as director of the fisheries and forestry departments.

I guess that is the answer. Could be a Nobel in physics coming his way too.

[BabySun]

@MaxYakov - you?no,no - I think,you might be even academic;actually it was just one individual,who pissed me off.

I believe people have sound minds,but fans of TV tend to write posts after practicing scientific experiments with water known as firewater.

With you - there is another problem - you have agenda

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?

[MaxYakov]

So per day costs; 28 l x 1100 boats x 24 hours x 35B equals about 26 million baht per day minimum on fuel alone.

Could there have been a deal worked out with PTT or some other fuel provider, in which someone gets a nice cut of profits, before they went ahead with this?

Does anyone know the details of how Plodprasop became so rich?

The wealthiest Cabinet minister is Science and Technology Minister Plodprasop Suraswadi with declared net assets of 963.5 Million Baht. Plodprasop has spent much of his career in government service in areas related to natural resources, including as director of the fisheries and forestry departments.

Associated Press

http://gulftoday.ae/...30d3cf4910.aspx

Thanks for the link, Buchholz. I'll attempt to suppress the puns w/r to this big fish. I'm changing my position on him, so ... swipe away, like a Grizzly on an Alaskan river!

[MaxYakov]

@MaxYakov - you?no,no - I think,you might be even academic;actually it was just one individual,who pissed me off.

I believe people have sound minds,but fans of TV tend to write posts after practicing scientific experiments with water known as firewater.

With you - there is another problem - you have agenda

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?

I have to agree with your appraisal of TV fans.

So 'firewater' is not my problem, huh? And there is a 'problem' with my having an 'agenda', huh?

What do you think that 'agenda' is ?

[longway]

Thanks, again longway. I had missed this post when I was replying to Buchholz's post. This is what I was looking for. I believe there are some adjustments in order, I believe because the boats are moored:

35 percent is given up to the atmosphere in heat

- To the water, mostly, in this case - Unintended Consequence

25 percent is given up in heat and vibration absorbed by surrounding water

- Losses to heat again?

10 percent is given up to overcome wave resistance

- Does not apply to the case of a moored vessel

6 percent to overcome wave formation and prop wash against the hull

- Overcome wave formation doesn't apply, prop wash against hull?

7 percent to overcome skin friction

- Does not apply

2 percent is wasted in friction at the propeller shaft

- Maybe the Minister can find a way to do his experiment without turning the screws?

1 percent to overcome air resistance

- Does not apply

This leaves about 13-14 percent of the original energy to turn the propeller.

Rough, adjusted efficiency estimate based on the fact that the boats are moored:

100% - (35% (heat) +25% (more heat/vibes) +1% (hull prop wash - arguable) +2% (prop shaft)) = 37%

I'm wondering about the 40% total loss between both atmospheric, water jacket and vibration.

Thanks Again for the research and effort.

Yeah I saw that, but decided to stick with the 15% as there may be other factors that negate those gains. It does say that 15% goes into turning the propellor, nothing about propellor effciency in pushing water in the way they hope.

And that's the figure ResX came up with too and he seems to know what he is talking about, unlike me.

Overall I come to think its a very serious endevour they are undertaking, it goes far beyond a publicity stunt, and I hope it has some good effect.

[MaxYakov]

Thanks, again longway. I had missed this post when I was replying to Buchholz's post. This is what I was looking for. I believe there are some adjustments in order, I believe because the boats are moored:

35 percent is given up to the atmosphere in heat

- To the water, mostly, in this case - Unintended Consequence

25 percent is given up in heat and vibration absorbed by surrounding water

- Losses to heat again?

10 percent is given up to overcome wave resistance

- Does not apply to the case of a moored vessel

6 percent to overcome wave formation and prop wash against the hull

- Overcome wave formation doesn't apply, prop wash against hull?

7 percent to overcome skin friction

- Does not apply

2 percent is wasted in friction at the propeller shaft

- Maybe the Minister can find a way to do his experiment without turning the screws?

1 percent to overcome air resistance

- Does not apply

This leaves about 13-14 percent of the original energy to turn the propeller.

Rough, adjusted efficiency estimate based on the fact that the boats are moored:

100% - (35% (heat) +25% (more heat/vibes) +1% (hull prop wash - arguable) +2% (prop shaft)) = 37%

I'm wondering about the 40% total loss between both atmospheric, water jacket and vibration.

Thanks Again for the research and effort.

Yeah I saw that, but decided to stick with the 15% as there may be other factors that negate those gains. It does say that 15% goes into turning the propellor, nothing about propellor effciency in pushing water in the way they hope.

And that's the figure ResX came up with too and he seems to know what he is talking about, unlike me.

Did ResX come up with the efficiency breakdown for you? He says he's a dam water expert, not an expert on boat propulsion efficiency.

Respectfully, you shouldn't include items from a moving boat efficiency breakdown that don't pertain to moored boats. Either that or find a moored boat efficiency breakdown (Good Luck with that). It would be difficult to justify including elements that would be patently impossible to affect a moored boat, don't you think? Unless you want to change the problem and have the boats zooming around the river. instead.

At least you're not going into deep Fantasyland with the Minister and some other people by running the numbers on 75 x 10³ boats. That's a plus!

I'm going to dig up the flow numbers on the other two rivers I researched day before yesterday. However, I could find only the yearly average m³ numbers for both. So I came up with some pretty OTW estimates for flood level.

[ResX]

That is not the situation we are looking for. If we can "put" a boat inside the discharge tunnel and its propeller provides thrust in the direction of flow, holding the gate opening to be the same, what do you think? Do you think that its flow rate will increase higher than 40m3/s?

Sorry for the temerity to debate a hydrologist but one more experiment.

Let's put a huge diameter pipe along the bottom of the river for 20 meters with a powerful pump inside. I concede that the water level at the upstream intake end will lower and the "tilt" of the river will steepen upstream, increasing the flow. However at the output end of our pump we find that we have increased the river level by an identical amount which flows away equally in all directions, with a slight bias toward downstream. However this is all immediately negated by the newly-formed upstream gradient we create as the humped water at the outlet now has an even steeper and far shorter gravity gradient to follow back upstream into the hole we created at the intake end. Result - localized circular flow in an open system with zero effect on the overall system flow..

First of all I just realized only after a few days our main discussion may not start up with the same model for control volume. I'm referring to the control volume for the flood areas of interest analogy to control volume of a water reservoir. Alternative model is natural river system control volume. I will elaborate later.

[crazygreg44]

let me add my five cents to all these backwater mathematicans and kindergarden physicists. All their marvellous calculations miss the most important factor ! This is, that all the waters of the Chao Phraya river are a massive,strong KINETIC MASS at RESISTANCE, almost standstill minus the actual flow, which acts like a wall of thick concrete you try to bring down by throwing Elephants doodoo against it. The waters being forced downstream by thousands of propellers will LOOSE THEIR MOMENTUM after few yards distance. The sheer mass and the volume of the water against which they are thrown, will zap kill dead any kinetic energy created by the propellers. Spit against the full moon and tell me how much of the force arrives there, that's what you're trying to "proove" . . . .

what a lovely madhouse, I am beginning to like it. Makes my day, every day since the discussion started . . . . . !!!

[MaxYakov]

let me add my five cents to all these backwater mathematicans and kindergarden physicists. All their marvellous calculations miss the most important factor ! This is, that all the waters of the Chao Phraya river are a massive,strong KINETIC MASS at RESISTANCE, almost standstill minus the actual flow, which acts like a wall of thick concrete you try to bring down by throwing Elephants doodoo against it. The waters being forced downstream by thousands of propellers will LOOSE THEIR MOMENTUM after few yards distance. The sheer mass and the volume of the water against which they are thrown, will zap kill dead any kinetic energy created by the propellers. Spit against the full moon and tell me how much of the force arrives there, that's what you're trying to "proove" . . . .

what a lovely madhouse, I am beginning to like it. Makes my day, every day since the discussion started . . . . . !!!

You're not the first poster on this topic to assert that the river will somehow 'zap kill dead any kinetic energy created by the propellers' (or words to that effect). As with a previous poster, I submit this Conservation of Energy article for you to read. While some may attribute physical anomalies of the Chao Phraya to the Goddess of Water, I'm of the opinion that the same physical laws are operating in Thailand that are operating elsewhere in the universe (including Farangland). I could be wrong about that - TiT.

I wouldn't think that spitting against the moon (full or otherwise) is on The Minister's agenda, but anything may be possible with him. If he does launch such an experiment, I'm sure TV will be ready to start another topic and the Thai people and government (and the remainder of the world) will follow its progress with great interest.

Cheers and Thanks for the $0.05!

[longway]

That is not the situation we are looking for. If we can "put" a boat inside the discharge tunnel and its propeller provides thrust in the direction of flow, holding the gate opening to be the same, what do you think? Do you think that its flow rate will increase higher than 40m3/s?

Sorry for the temerity to debate a hydrologist but one more experiment.

Let's put a huge diameter pipe along the bottom of the river for 20 meters with a powerful pump inside. I concede that the water level at the upstream intake end will lower and the "tilt" of the river will steepen upstream, increasing the flow. However at the output end of our pump we find that we have increased the river level by an identical amount which flows away equally in all directions, with a slight bias toward downstream. However this is all immediately negated by the newly-formed upstream gradient we create as the humped water at the outlet now has an even steeper and far shorter gravity gradient to follow back upstream into the hole we created at the intake end. Result - localized circular flow in an open system with zero effect on the overall system flow..

Why would the level drop at the upstream end? It would be immediately replaced by 'new' water, the point is to increase water discharge as they need the rivers to drain the flood plains faster.

[HomeyG]

I'm looking for some data on the Chao praya:

average discharge flow,

main stream velocity,

average width and depth,

level difference and length in the endangered city area

My curiosity has led me to ask about this on a physics forum. They need more information.

It's an interesting debate. My first instinct is that any gain is completely absorbed and lost within 30 meters downstream of the props.

Also, how far, how many kilometers from these boats to the gulf of Thailand?

[JetsetBkk]

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.

<snip>

Agreed - not zero as some say, but very small.

[cloudhopper]

That is not the situation we are looking for. If we can "put" a boat inside the discharge tunnel and its propeller provides thrust in the direction of flow, holding the gate opening to be the same, what do you think? Do you think that its flow rate will increase higher than 40m3/s?

Sorry for the temerity to debate a hydrologist but one more experiment.

Let's put a huge diameter pipe along the bottom of the river for 20 meters with a powerful pump inside. I concede that the water level at the upstream intake end will lower and the "tilt" of the river will steepen upstream, increasing the flow. However at the output end of our pump we find that we have increased the river level by an identical amount which flows away equally in all directions, with a slight bias toward downstream. However this is all immediately negated by the newly-formed upstream gradient we create as the humped water at the outlet now has an even steeper and far shorter gravity gradient to follow back upstream into the hole we created at the intake end. Result - localized circular flow in an open system with zero effect on the overall system flow..

Why would the level drop at the upstream end? It would be immediately replaced by 'new' water, the point is to increase water discharge as they need the rivers to drain the flood plains faster.

It will drop there because water is being removed as per ResX explanation above. It is being replaced as you say but the flow of replacement water is coming from the output side of the pump where the water level is even higher, not from upstream. Water in an unpressurized system will only flow when there is a gravity gradient between unequal heights.