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

[ResX]

If we allow flood water to flow down naturally it will follow free surface flow equation Q= cLH^1.5. Q is volumetric flow rate, cL empirical constant and H height of water column above riverbed. Or you want to use Manning equation.... This is actually the natural way water can transport itself given even a slight pressure gradient for it to move. It builds up itself layer by layer to increase H so that Q increases. Allow it undisturbed, the higher the flood flow the higher it builds up H. This nature of water flow that makes the flood looks the way we usually see.

,

If you observe free surface flow equation you can see that the water velocity higher on the top and zero at the bottom. If this equation governs out going discharge of a a bottleneck cross section the flood plain just upstream will be flooded. The water velocity is almost zero and hydraulic gradient between the bottle neck section and upstream end of the "pond" has been created is very small. It may take a long time before the this pond to be emptied. The nature of this discharge formula in fact is used for flood control for a very big reservoir (surprisingly your Bhumibol does not have this kind of flood control gate-as far as I can see-This is one of the reasons why the flood is soooo big) to slow down water release to downstream. But you don't want this equation dominates at downstream. What shall you do? Let we make up some numbers for one of the bottle necks.

Q= 4500m3/s. H =5m. Then cL 866. That makes Q=866H^1.5. Assuming the flood plain water surface area 5km2. Then we have about 25million cubic meter of water that need to be drained out based on that equation. How we can make a 25million m3 above faster? Just put t pump and suck the water out via the bottle neck. So the discharge equation for the pond becomes

Q = 866H^1.5 + pump discharge. Then the pond water level is going down faster. Or just force the water out using boat propeller. The equation becomes:

Q= 866H^1.5 + propeller discharge.

Either one the discharge will be higher. As long as the flood plain of this kind that propellers can provide meaningful impact. Otherwise .....

Edited October 20, 2011 by ResX

[TommyDee]

If we allow flood water to flow down naturally it will follow free surface flow equation Q= cLH^1.5. Q is volumetric flow rate, cL empirical constant and H height of water column above riverbed. Or you want to use Manning equation.... This is actually the natural way water can transport itself given even a slight pressure gradient for it to move. It builds up itself layer by layer to increase H so that Q increases. Allow it undisturbed, the higher the flood flow the higher it builds up H. This nature of water flow that makes the flood looks the way we usually see.

,

If you observe free surface flow equation you can see that the water velocity higher on the top and zero at the bottom. If this equation governs out going discharge of a a bottleneck cross section the flood plain just upstream will be flooded. The water velocity is almost zero and hydraulic gradient between the bottle neck section and upstream end of the "pond" has been created is very small. It may take a long time before the this pond to be emptied. The nature of this discharge formula in fact is used for flood control for a very big reservoir (surprisingly your Bhumibol does not have this kind of flood control gate-as far as I can see-This is one of the reasons why the flood is soooo big) to slow down water release to downstream. But you don't want this equation dominates at downstream. What shall you do? Let we make up some numbers for one of the bottle necks.

Q= 4500m3/s. H =5m. Then cL 866. That makes Q=866H^1.5. Assuming the flood plain water surface area 5km2. Then we have about 25million cubic meter of water that need to be drained out based on that equation. How we can make a 25million m3 above faster? Just put t pump and suck the water out via the bottle neck. So the discharge equation for the pond becomes

Q = 866H^1.5 + pump discharge. Then the pond water level is going down faster. Or just force the water out using boat propeller. The equation becomes:

Q= 866H^1.5 + propeller discharge.

Either one the discharge will be higher. As long as the flood plain of this kind that propellers can provide meaningful impact. Otherwise .....

I am loving this semi-useless thread but I am also very very stupid, i am not sure if there is a conection HOWEVER, in your mathmatics and phyics i just have one question. well probably 2.

you, regardless of the amount, state that the exit for the water is a bottle neck. you assume that exit capacity to be Q

you now partially block that exit with a static mounted propeller.

therefore add resistance to the natural flow lets call that reduction amount Y

so regardless of the efficiency of the new propeller unit, your equasion cant be right, because you have not deducted the loss Y.

so wouldnt it be.. Q-y+ propeller discharge ( which i still think is a small amount)??

at the end of the day I admit to being a complete idiot so have probable misread all of this and need to go back to page one

Edited October 20, 2011 by TommyDee

[nocturn]

what a bunch of wanke_rs you lot are

[GentlemanJim]

what a bunch of wanke_rs you lot are

100% correct. they have totally hijacked and destroyed the thread. ResX has gone from not knowing anything at the start to now seeming to profess to hold a PhD in hydrodynamics. The whole thread for the last 15 pages is complete arse. It is like being in a pub watching a bunch of pi**heads trying to solve the question to life and the Universe. Utter drivel and the thread should have been moved to the farang pub forum days ago.

[bkkjames]

I heard that if we wait till 21/12/2012 when the planets line-up x will = y x mc hammer and we won't be able to touch this or that.

[JetsetBkk]

I'm afraid that is not the case. The fact that the parcel of water that this entire circulation is occurring within is moving with respect to the bank or away from the pump is irrelevant.. The speed of the current will only (and very slightly with the low current vs. accelerated water speed in this case) distort the shape of the return current (as will the force of the pump). No matter how powerful a pump is used (in this way) equilibrium will be eventually restored by that mechanism and zero percent of that energy will add to the net downstream energy..

Very interesting. Especially this bit:

"equilibrium will be eventually restored by that mechanism and zero percent of that energy will add to the net downstream energy"

So please explain why, when these boats are no longer anchored or tied to other boats that are anchored, they will start to move upstream.

If your theory is correct you have invented free energy!

Better patent this idea quick!

[Buchholz]

what a bunch of wanke_rs you lot are

100% correct. they have totally hijacked and destroyed the thread. ResX has gone from not knowing anything at the start to now seeming to profess to hold a PhD in hydrodynamics. The whole thread for the last 15 pages is complete arse. It is like being in a pub watching a bunch of pi**heads trying to solve the question to life and the Universe. Utter drivel and the thread should have been moved to the farang pub forum days ago.

Once the 1,000 Boats thread gets to 1,000 posts... it probably will.

According to extensive scientific calculations, that will most likely occur sometime this afternoon.

[BabySun]

what a bunch of wanke_rs you lot are

100% correct. they have totally hijacked and destroyed the thread. ResX has gone from not knowing anything at the start to now seeming to profess to hold a PhD in hydrodynamics. The whole thread for the last 15 pages is complete arse. It is like being in a pub watching a bunch of pi**heads trying to solve the question to life and the Universe. Utter drivel and the thread should have been moved to the farang pub forum days ago.

I think you are right,mate.I also think,that ResX holds phd.

[ResX]

If we allow flood water to flow down naturally it will follow free surface flow equation Q= cLH^1.5. Q is volumetric flow rate, cL empirical constant and H height of water column above riverbed. Or you want to use Manning equation.... This is actually the natural way water can transport itself given even a slight pressure gradient for it to move. It builds up itself layer by layer to increase H so that Q increases. Allow it undisturbed, the higher the flood flow the higher it builds up H. This nature of water flow that makes the flood looks the way we usually see.

,

If you observe free surface flow equation you can see that the water velocity higher on the top and zero at the bottom. If this equation governs out going discharge of a a bottleneck cross section the flood plain just upstream will be flooded. The water velocity is almost zero and hydraulic gradient between the bottle neck section and upstream end of the "pond" has been created is very small. It may take a long time before the this pond to be emptied. The nature of this discharge formula in fact is used for flood control for a very big reservoir (surprisingly your Bhumibol does not have this kind of flood control gate-as far as I can see-This is one of the reasons why the flood is soooo big) to slow down water release to downstream. But you don't want this equation dominates at downstream. What shall you do? Let we make up some numbers for one of the bottle necks.

Q= 4500m3/s. H =5m. Then cL 866. That makes Q=866H^1.5. Assuming the flood plain water surface area 5km2. Then we have about 25million cubic meter of water that need to be drained out based on that equation. How we can make a 25million m3 above faster? Just put t pump and suck the water out via the bottle neck. So the discharge equation for the pond becomes

Q = 866H^1.5 + pump discharge. Then the pond water level is going down faster. Or just force the water out using boat propeller. The equation becomes:

Q= 866H^1.5 + propeller discharge.

Either one the discharge will be higher. As long as the flood plain of this kind that propellers can provide meaningful impact. Otherwise .....

I am loving this semi-useless thread but I am also very very stupid, i am not sure if there is a conection HOWEVER, in your mathmatics and phyics i just have one question. well probably 2.

you, regardless of the amount, state that the exit for the water is a bottle neck. you assume that exit capacity to be Q

you now partially block that exit with a static mounted propeller.

therefore add resistance to the natural flow lets call that reduction amount Y

so regardless of the efficiency of the new propeller unit, your equasion cant be right, because you have not deducted the loss Y.

so wouldnt it be.. Q-y+ propeller discharge ( which i still think is a small amount)??

at the end of the day I admit to being a complete idiot so have probable misread all of this and need to go back to page one

Nice remark. I will right back soon.

[cloudhopper]

"equilibrium will be eventually restored by that mechanism and zero percent of that energy will add to the net downstream energy"

So please explain why, when these boats are no longer anchored or tied to other boats that are anchored, they will start to move upstream.

An untied boat will move in reaction to the thrust. When thrust is removed the boat will come to rest after a few boat lengths, not coast for miles. The water thrust aft by the prop will also quickly stop moving aft and curve away from the thrust line as I already described because it is not contained in any way. It makes no difference if this takes place on a lake or a river nor the direction of thrust or whether the boat is tied or not. The flow rate of the river simply cannot be increased by this method as all of the kinetic energy added either flows in a circle or is dissipated as heat.

[MaxYakov]

Elevation which can be artificially reproduced with an a accelerant such as a pump..

Quite so because water is incompressible however in our case of the moored boats both intake and output of the 'pump' remain within the river. The effect is then creating a depression in river elevation at the pump intake and creating an upward bulge at the outlet. The high pressure bulge forces water outward in ALL directions equally and the accelerated water flows in a 3D loop back into the depression created upstream at the intake. Zero water is accelerated directly downstream for any significant distance - it ALL curves back toward the low pressure area.

That only applies in magnitude in a static body of water not in a flowing river as the water continues to flow downstream with momentum just at a quicker pace, there will be some backflow but it is minimal in relation to the added downstream flow...

Agree with WarpSpeed. Additionally, water 'flows into a 3D loop back into the depression upstream of the intake'? Are we talking meteorology here? Would that be tropical depression? The law of inertia have been suspended as well to support this? The accelerated water has mass, velocity and direction. If it didn't, boats could not be propelled efficiently, or at all.

I've been out of it folks due to a sprained ankle. Have been loosely following things and have been working on my energy model which is based on an ideal situation, to reduce nattering, what I consider, unimportant details. I don't want to post all the details/math in this post, but will give a summary:

500 boats delivering 1000 HP at propeller output (not at shaft input and addresses ONLY the Chao Phraya river - not the other two).

This simplifies/eliminates distractions such as fuel-to-engine efficiency, propeller efficiency, etc which I consider to be separate issues.

Recent flow-rate for Chao Phraya at 420 x 10⁶ m³/day

Speed of Chao Phraya river used: 1 m/second - This is an estimate and, perhaps, too low/slow.

Changes in this value are a square factor by the kinetic energy formula and will have a large affect the total KE of the river and the total KE percentage increase by the total 500,000 HP (at propeller output, not engine HP).

========> Kinetic energy of river is increased by about 15%

Note: If most of the kinetic energy added is directed with the current flow and there is minimal loss of energy due to transformation to heat and energy does not 'disappear', then (since the mass of the water has not changed) the energy increase of the river water can only be manifested only as a higher velocity of the river water.

Incidentally, given the above parameters, several of you could apply the KE formula to validate the 15% result. HP-to-Joules conversion that I used is: 1 HP = 746 Joules (from an internet converter).

500,000 HP, directly into the Chao Phraya has got to have some effect, wouldn't you think? I let you folks kick around what that effect would/might be.

Comments?

Edited October 21, 2011 by MaxYakov

[Thaddeus]

I've been out of it folks due to a sprained ankle.

How did you sprain your ankle, trying to count to twenty?

Sorry, couldn't resist it.

[AleG]

Agree with WarpSpeed. Additionally, water 'flows into a 3D loop back into the depression upstream of the intake'? Are we talking meteorology here? Would that be tropical depression? The law of inertia have been suspended as well to support this? The accelerated water has mass, velocity and direction. If it didn't, boats could not be propelled efficiently, or at all.

I've been out of it folks due to a sprained ankle. Have been loosely following things and have been working on my energy model which is based on an ideal situation, to reduce nattering, what I consider, unimportant details. I don't want to post all the details/math in this post, but will give a summary:

500 boats delivering 1000 HP at propeller output (not at shaft input and addresses ONLY the Chao Phraya river - not the other two).

This simplifies/eliminates distractions such as fuel-to-engine efficiency, propeller efficiency, etc which I consider

to be a separate issues.

Recent flow-rate for Chao Phraya at 420 x 10⁶ m³/day

Speed of Chao Phraya river used: 1 m/second - This is an estimate and, perhaps, too low/slow.

Changes in this value are a square factor by the kinetic energy formula and will have a large affect the total KE of the river

and the total KE percentage increase by the total 500,000 HP (at propeller output, not engine HP).

========> Kinetic energy of river is increased by about 15%

Note: If most of the kinetic energy added is directed with the current flow and there is minimal loss of energy due to transformation to heat and energy does not 'disappear', then (since the mass of the water has not changed) the energy increase of the river water can only be manifested only as a higher velocity of the river water.

Incidentally, given the above parameters, several of you could apply the KE formula to validate the 15% result. HP-to=Joules conversion that I used is: 1 HP = 746 Joules (from an internet converter).

500,000 HP, directly into the Chao Phraya has got to have some effect, wouldn't you think? I let you folks kick around what that effect would/might be.

Comments?

You are missing several factors, most importantly what I pointed out earlier: most of the boats used on this operation where in mid river, not moored to anything, therefore as long as they were not accelerating the thrust from the propeller is a force equal and opposite to the drag of the hull, so the net sum of force and energy delivered to the flow of water is ZERO. In simple terms the boat is pushing as much water as it is slowing down.

Second, most of the boats used are nowhere close to 1000HP in engine power, not even close. Those small river "buses", in my uninformed opinion, shouldn't have more than 100HP at most, although someone with actual data may want to chime in.

Third, the vector of the thrust at the propeller point is rearwards, but it doesn't stay that way for long due to turbulence, if it would then you wouldn't see the water churning around behind a propeller, it would be a linear flow. Some of the energy is vectored downriver, most of it is diverted in all other directions. I would guess that the net result, after you subtract the "useful" vector from the hull drag in the water you end up with a pittance of benefit out of the effort.

Fourth the Chao Phraya meanders a lot, so even if the flow from the propeller would follow the thrust line for a significant distance, then it would only end up lapping some shore or another.

Fifth the water pushed back from the propellers would find resistance from slower water in the river flow, since you can't compress water (meaningfully) the way the resistance manifests is in a local rise in the water level which will try to settle in all directions, not just down the thrustline, so you have a bulge behind the prop that spreads back, to the sides and also forward. This contributes called recirculation or a vortex ring state, where the water (or fluid) assumes a donut shaped flow around a propeller, reducing efficiency significantly. (I get to suffer that phenomena regulary flying RC helicopters). The higher the difference in speed between the propeller downwash and the surrounding fluid the more likely it is to develop recirculation, thus the anchored boats going full gas should be suffering a significant loss of efficiency from this.

[wallswod]

What a sad, very sad suggestion.

And the morons actually did it !!!!!

[Buchholz]

What a sad, very sad suggestion.

And the morons actually did it !!!!!

Topped off by announcements that it worked !!!!

.

[ResX]

what a bunch of wanke_rs you lot are

100% correct. they have totally hijacked and destroyed the thread. ResX has gone from not knowing anything at the start to now seeming to profess to hold a PhD in hydrodynamics. The whole thread for the last 15 pages is complete arse. It is like being in a pub watching a bunch of pi**heads trying to solve the question to life and the Universe. Utter drivel and the thread should have been moved to the farang pub forum days ago.

I think you are right,mate.I also think,that ResX holds phd.

Close to but yet there. Master degree is a little bit too low, since to date 2 phd students used to seek my advice in their works. A few phd holders asked my advice too. But in one specific area that I'm very good at about surface water flow management.

To correct the statement that one of our friends made about me. No I did not learn about hydro dynamics over the last one week. I can recall it correctly. It is exactly 31 years 6 months.

[cloudhopper]

Say there ResX just curious what university?

edit - sorry, which university?

Edited October 21, 2011 by cloudhopper

[Spalpeen]

Maybe they're using the wrong kind of boats. What they should be using is 1,000 stern wheel paddle steamers.

.

I see many well intentioned efforts in this thread at calculating the river flow characteristics. I note also that the Thai government has a large hydrology department devoted to the study and management of Thailands river systems, although they don't seem to have much to say on the present situation. The fact is that this kind of flooding is beyond the scope of simple calculation. The only realistic way to predict the progress of this kind of flooding is to look at records of previous flooding events and to extrapolate from that.

There's another aspect of this situation that seems to have attracted little attention so far. If the water treatment and sewage treatment works of a city are inundated you can rapidly find yourself without either drinking water or working sewers. In a city of 12m people that's not a good thing. Also, I know that the MRT was designed to resist flooding events, but if the flooding gets out of control this too could be in danger.

[ResX]

Say there ResX just curious what university?

edit - sorry, which university?

I'm not an academician. Not in Thailand.

Let me try to build up a simple idealized model regarding the subject we are currently discussing. We know that the current flow of CP river is 420 X 10^6m3 (4861m3/s). Assuming we can build a surface water tunnel (2km wide) right from Bhumibol dam up to the river mouth. The total distance is 500km (I just made up a number). At the Bhumibol side, water level elevation is 250m above sea level. Near river water level elevation is 2 m from the upper flow level and exactly zero from the riverbed. The water velocity for full laminar flow is 1.22m/s (it is definitely laminar anyway) . Don't worry I have calculated it for you the water velocity is correct. Note that too that the only driving force that that moves a huge amount of water is PRESSURE GRADIENT, assuming you can take for granted gravitational acceleration is there. .

I ask you a question: Why the water moves from the Bhumibol dam to its river mouth? If you answer because of the gravity, then I will give you half of the scores. Why? Because the water inside the glass of the Bhumibol staff does not make up the river mouth. The right answer is because of the present of pressure gradient 250 meter for every 500km horizontal distance (Hydraulic gradient =0.5m/km) and nothing stops the water to flow down due to gravitational force.

We let the water flow undisturbed. It flows down in harmony at the speed of 1.22m/s as long as 4,861m3/s is supplied by the Bhumibol dam. Let us start it from here the effect adding kinetic energy to the flow. First experiment. Let put the pump at the outlet. Let us assume the pump has discharge capability of 1000m3/s. I don't to put a boat for this test to prevent the other the other debated subject to enter into this conceptual discussion. What will happen next?

Anybody wish to try? Note that the actual scenario is definitely not as simple as this idealized model. But the Physics laws do not change just because the system of equations become more complex.

No prize for the right answer.

Hint: Please don't solve using the second order differential equation and using Navier -Stokes Equations. They are not required to solve this type of problem.

Edited October 21, 2011 by ResX

[JetsetBkk]

"equilibrium will be eventually restored by that mechanism and zero percent of that energy will add to the net downstream energy"

So please explain why, when these boats are no longer anchored or tied to other boats that are anchored, they will start to move upstream.

An untied boat will move in reaction to the thrust. When thrust is removed the boat will come to rest after a few boat lengths, not coast for miles. The water thrust aft by the prop will also quickly stop moving aft and curve away from the thrust line as I already described because it is not contained in any way. It makes no difference if this takes place on a lake or a river nor the direction of thrust or whether the boat is tied or not. The flow rate of the river simply cannot be increased by this method as all of the kinetic energy added either flows in a circle or is dissipated as heat.

"The boats will move in reaction to the thrust" Correct! Newton's Third Law of Motion. Exactly my point.

So when the boats are anchored, the "thrust" as you call it cannot push the boats upstream. Where does it go? It goes into the water and pushes it downstream. This is Newton's Second law: the acceleration a of a body is parallel and directly proportional to the net force and inversely proportional to the mass.

You say this water will stop moving aft and will curve away from the thrust line. Why? This is Newton's First law: The velocity of a body remains constant unless the body is acted upon by an external force. In this case the "body" is water molecules colliding with slower water molecules.

Finally, a consequence of the law of conservation of energy that energy can neither be created nor be destroyed. So the fast moving water molecules bash into the slower ones, giving them some energy. The fast ones slow down, the slow ones speed up.

It may look like "dissipation" but in fact the energy is still in the water - it has simply spread out, and the water is moving quicker, although after a few metres it'd be hard to detect. But the ability to detect this minute increase in speed is not the issue.

The issue is that the water will be moving quicker.

The other aspect of this discussion is the effectiveness of this theory. I think we can all agree that the minute amount of extra energy being added to the river is so small compared to the huge mass of water that it has to act upon, that its effectiveness in reducing flooding is virtually zero - not quite zero, but very close.

On the other hand, if some people are sleeping a little happier in their semi-submerged homes believing that the government is doing everything it can to help them, then that is a good thing. Let the boats carry on, let the people feel happier.

And now,

[WarpSpeed]

for what ever reason

http://www.tulane.edu/~sanelson/geol204/riversystems.htm

Thank you for that it confirms a lot of what I've been saying..

[bkkjames]

This topic should be closed: they came they tried and had no effect (that anyone can see). Are they still using the boats to push the water? No?

[GentlemanJim]

what a bunch of wanke_rs you lot are

100% correct. they have totally hijacked and destroyed the thread. ResX has gone from not knowing anything at the start to now seeming to profess to hold a PhD in hydrodynamics. The whole thread for the last 15 pages is complete arse. It is like being in a pub watching a bunch of pi**heads trying to solve the question to life and the Universe. Utter drivel and the thread should have been moved to the farang pub forum days ago.

I think you are right,mate.I also think,that ResX holds phd.

Close to but yet there. Master degree is a little bit too low, since to date 2 phd students used to seek my advice in their works. A few phd holders asked my advice too. But in one specific area that I'm very good at about surface water flow management.

To correct the statement that one of our friends made about me. No I did not learn about hydro dynamics over the last one week. I can recall it correctly. It is exactly 31 years 6 months.

I was being flippant about your qualifications ResX. If what you say is even remotely true then I am afraid it just makes matters even worse. If you possess any form of scientific background then you would not make such ridiculous statements, assumptions and "just making number up". Your approach to the entire problem concerning the OP is completely absolutely wrong, and the assumptions you make and attempt to solve the problem using the most basic and fundamental maths and equations proves without doubt you have no grasp on the complexities involved with the solution of the problem. Because of that it is a waste of bandwith, time and energy wading through the thread. I can only come to one of two conclusions, a) you are trolling to try and wind people up by continuing to come up with non applicable physics and statements, or you really believe that you are on to something...you are not. Sorry, this is hard, but it's fair.

[ResX]

"equilibrium will be eventually restored by that mechanism and zero percent of that energy will add to the net downstream energy"

So please explain why, when these boats are no longer anchored or tied to other boats that are anchored, they will start to move upstream.

An untied boat will move in reaction to the thrust. When thrust is removed the boat will come to rest after a few boat lengths, not coast for miles. The water thrust aft by the prop will also quickly stop moving aft and curve away from the thrust line as I already described because it is not contained in any way. It makes no difference if this takes place on a lake or a river nor the direction of thrust or whether the boat is tied or not. The flow rate of the river simply cannot be increased by this method as all of the kinetic energy added either flows in a circle or is dissipated as heat.

"The boats will move in reaction to the thrust" Correct! Newton's Third Law of Motion. Exactly my point.

So when the boats are anchored, the "thrust" as you call it cannot push the boats upstream. Where does it go? It goes into the water and pushes it downstream. This is Newton's Second law: the acceleration a of a body is parallel and directly proportional to the net force and inversely proportional to the mass.

You say this water will stop moving aft and will curve away from the thrust line. Why? This is Newton's First law: The velocity of a body remains constant unless the body is acted upon by an external force. In this case the "body" is water molecules colliding with slower water molecules.

Finally, a consequence of the law of conservation of energy that energy can neither be created nor be destroyed. So the fast moving water molecules bash into the slower ones, giving them some energy. The fast ones slow down, the slow ones speed up.

It may look like "dissipation" but in fact the energy is still in the water - it has simply spread out, and the water is moving quicker, although after a few metres it'd be hard to detect. But the ability to detect this minute increase in speed is not the issue.

The issue is that the water will be moving quicker.

The other aspect of this discussion is the effectiveness of this theory. I think we can all agree that the minute amount of extra energy being added to the river is so small compared to the huge mass of water that it has to act upon, that its effectiveness in reducing flooding is virtually zero - not quite zero, but very close.

On the other hand, if some people are sleeping a little happier in their semi-submerged homes believing that the government is doing everything it can to help them, then that is a good thing. Let the boats carry on, let the people feel happier.

And now,

You get it all right here mate. This is no longer the debating issue as I suggested a few days back. If anybody believes that it it only works for the first 10m and after that the water velocity returns to its original velocity, then he or she manages to destroy energy. This is a new innovation that we cannot comment. It is too advanced beyond the boundary that we can comprehend.

[GentlemanJim]

"equilibrium will be eventually restored by that mechanism and zero percent of that energy will add to the net downstream energy"

So please explain why, when these boats are no longer anchored or tied to other boats that are anchored, they will start to move upstream.

An untied boat will move in reaction to the thrust. When thrust is removed the boat will come to rest after a few boat lengths, not coast for miles. The water thrust aft by the prop will also quickly stop moving aft and curve away from the thrust line as I already described because it is not contained in any way. It makes no difference if this takes place on a lake or a river nor the direction of thrust or whether the boat is tied or not. The flow rate of the river simply cannot be increased by this method as all of the kinetic energy added either flows in a circle or is dissipated as heat.

"The boats will move in reaction to the thrust" Correct! Newton's Third Law of Motion. Exactly my point.

So when the boats are anchored, the "thrust" as you call it cannot push the boats upstream. Where does it go? It goes into the water and pushes it downstream. This is Newton's Second law: the acceleration a of a body is parallel and directly proportional to the net force and inversely proportional to the mass.

You say this water will stop moving aft and will curve away from the thrust line. Why? This is Newton's First law: The velocity of a body remains constant unless the body is acted upon by an external force. In this case the "body" is water molecules colliding with slower water molecules.

Finally, a consequence of the law of conservation of energy that energy can neither be created nor be destroyed. So the fast moving water molecules bash into the slower ones, giving them some energy. The fast ones slow down, the slow ones speed up.

It may look like "dissipation" but in fact the energy is still in the water - it has simply spread out, and the water is moving quicker, although after a few metres it'd be hard to detect. But the ability to detect this minute increase in speed is not the issue.

The issue is that the water will be moving quicker.

The other aspect of this discussion is the effectiveness of this theory. I think we can all agree that the minute amount of extra energy being added to the river is so small compared to the huge mass of water that it has to act upon, that its effectiveness in reducing flooding is virtually zero - not quite zero, but very close.

On the other hand, if some people are sleeping a little happier in their semi-submerged homes believing that the government is doing everything it can to help them, then that is a good thing. Let the boats carry on, let the people feel happier.

And now,

You get it all right here mate. This is no longer the debating issue as I suggested a few days back. If anybody believes that it it only works for the first 10m and after that the water velocity returns to its original velocity, then he or she manages to destroy energy. This is a new innovation that we cannot comment. It is too advanced beyond the boundary that we can comprehend.

There you go again! You seem to think that by applying a certain amount of energy your water system will retain that energy in the form of its forward momentum for ever. You are displaying a total lack of understanding of any of the laws of momentum, energy and thermal dynamics. Stop Trolling!

[WarpSpeed]

what a bunch of wanke_rs you lot are

Too deep for you nocturn? Feeling left behind , I'm guessing yes ..

Edited October 21, 2011 by WarpSpeed

[cloudhopper]

If anybody believes that it it only works for the first 10m and after that the water velocity returns to its original velocity, then he or she manages to destroy energy. This is a new innovation that we cannot comment. It is too advanced beyond the boundary that we can comprehend.

No energy is destroyed

all of the kinetic energy added either flows in a circle or is dissipated as heat.

This is not a new innovation but it is apparently beyond your comprehension.

[WarpSpeed]

what a bunch of wanke_rs you lot are

100% correct. they have totally hijacked and destroyed the thread. ResX has gone from not knowing anything at the start to now seeming to profess to hold a PhD in hydrodynamics. The whole thread for the last 15 pages is complete arse. It is like being in a pub watching a bunch of pi**heads trying to solve the question to life and the Universe. Utter drivel and the thread should have been moved to the farang pub forum days ago.

Oh dear, another one who'e feeling left behind and whinging about it..

[WarpSpeed]

"equilibrium will be eventually restored by that mechanism and zero percent of that energy will add to the net downstream energy"

So please explain why, when these boats are no longer anchored or tied to other boats that are anchored, they will start to move upstream.

An untied boat will move in reaction to the thrust. When thrust is removed the boat will come to rest after a few boat lengths, not coast for miles. The water thrust aft by the prop will also quickly stop moving aft and curve away from the thrust line as I already described because it is not contained in any way. It makes no difference if this takes place on a lake or a river nor the direction of thrust or whether the boat is tied or not. The flow rate of the river simply cannot be increased by this method as all of the kinetic energy added either flows in a circle or is dissipated as heat.

You keep focusing exclusively on the thrust that a prop creates on a boat in motion and completely disregarding the volume of water pushed past a stationary boat by the propellers..

Edited October 21, 2011 by WarpSpeed

[WarpSpeed]

Elevation which can be artificially reproduced with an a accelerant such as a pump..

Quite so because water is incompressible however in our case of the moored boats both intake and output of the 'pump' remain within the river. The effect is then creating a depression in river elevation at the pump intake and creating an upward bulge at the outlet. The high pressure bulge forces water outward in ALL directions equally and the accelerated water flows in a 3D loop back into the depression created upstream at the intake. Zero water is accelerated directly downstream for any significant distance - it ALL curves back toward the low pressure area.

That only applies in magnitude in a static body of water not in a flowing river as the water continues to flow downstream with momentum just at a quicker pace, there will be some backflow but it is minimal in relation to the added downstream flow...

Agree with WarpSpeed. Additionally, water 'flows into a 3D loop back into the depression upstream of the intake'? Are we talking meteorology here? Would that be tropical depression? The law of inertia have been suspended as well to support this? The accelerated water has mass, velocity and direction. If it didn't, boats could not be propelled efficiently, or at all.

I've been out of it folks due to a sprained ankle. Have been loosely following things and have been working on my energy model which is based on an ideal situation, to reduce nattering, what I consider, unimportant details. I don't want to post all the details/math in this post, but will give a summary:

500 boats delivering 1000 HP at propeller output (not at shaft input and addresses ONLY the Chao Phraya river - not the other two).

This simplifies/eliminates distractions such as fuel-to-engine efficiency, propeller efficiency, etc which I consider to be separate issues.

Recent flow-rate for Chao Phraya at 420 x 10⁶ m³/day

Speed of Chao Phraya river used: 1 m/second - This is an estimate and, perhaps, too low/slow.

Changes in this value are a square factor by the kinetic energy formula and will have a large affect the total KE of the river and the total KE percentage increase by the total 500,000 HP (at propeller output, not engine HP).

========> Kinetic energy of river is increased by about 15%

Note: If most of the kinetic energy added is directed with the current flow and there is minimal loss of energy due to transformation to heat and energy does not 'disappear', then (since the mass of the water has not changed) the energy increase of the river water can only be manifested only as a higher velocity of the river water.

Incidentally, given the above parameters, several of you could apply the KE formula to validate the 15% result. HP-to-Joules conversion that I used is: 1 HP = 746 Joules (from an internet converter).

500,000 HP, directly into the Chao Phraya has got to have some effect, wouldn't you think? I let you folks kick around what that effect would/might be.

Comments?

Well done Max!! Tried to hold down the fort while you were gone, good to have you back take care of that ankle..

Edited October 21, 2011 by WarpSpeed