17 minutes ago, impulse said:

 

It will eventually be at the same speed as the rest of the water, true.  But you've added kinetic energy to the system (in the correct direction) so the whole system will be flowing faster.  Meaning the rate at which the water flows to the sea will be increased.

 

How much faster, and whether it's an effective solution will take more figuring than I've ever read here from any geniuses at TVF.  But suffice it to say that axial flow pumps (which is what a boat's propeller is) are a very widely used method of moving water around.

 

Agreed, incrementally. Is that increment enough to make a difference? If the river is (just hypothetically) 200m wide and 20m deep where the ships are stationed, we’re looking at a cross-section of 4,000 square meters. How big are the props? If they’re say, 4 meters, we’re looking at less than 13 square meters per prop. Twin props, six ships, we’ve got 12 props, so about 150 square meters total. So we’re looking at the props covering about 4% of the river’s cross-section. A small amount of that (which I don’t know) will be brought around the prop to go through again. So...we’re covering less than 4%. As the effected river water works to stabilize its speed with the “normal” speed of the flood waters, and as the river widens, the effect will be quickly dissapted. Will the river flow 3-4% faster? Not after just a very few meters.

 

Axial flow pumps work very well because the impellers, or propellers, are housed within a pipe. They do not have to contend with dissipation into surrounding waters until the job is done and the pipe ends. It’s quite different from being immersed in pure liquid without a tube to direct the water.

Edited October 25, 20178 yr by noahvail

Who the hell's in charge here? Coco the clown? You would have thought that they would have learned from the international derision they received from the last time they tried this.

To make it work you have to place boat in tight channel,if not - you will create the reverse current,just go into toilet and watch how air there in ventilated?

5 minutes ago, noahvail said:

How big are the props? If they’re say, 4 meters, we’re looking at less than 13 square meters per prop. Twin props, six ships, we’ve got 12 props, so about 150 square meters total. So we’re looking at the props covering about 4% of the river’s cross-section. A small amount of that (which I don’t know) will be brought around the prop to go through again. So...we’re covering less than 4%. As the effected river water works to stabilize its speed with the “normal” speed of the flood waters, and as the river widens, the effect will be quickly dissapted. Will the river flow 3-4% faster? Not after just a very few meters.

 

The critical factor isn't the number or size of the props.  It's the amount of kinetic energy those props are adding to the system.  Which boils down to horsepower.  Add 30,000 HP to a system (in the correct direction- remember that velocity is a vector quantity- not a scalar), and I promise you it will flow faster.  Whether it makes a significant difference is all about the numbers.

 

The concept is sound.  Whether the implementation is or not is moot since they're holding a funeral ceremony tomorrow for the guy whose idea it was.

 

fluids flows from area of high pressure to low pressure - unfortunately the sea isnt accepting any more water and is at same or higher pressure than water in the river so this is just ridiculous. 

ashkale! You drink to much and your body can not accept more fluid,go take piss,then you take another bottle.

Mighty Ocean takes all the water from ChiaoPraya and all other rivers in the World,capito??

Edited October 25, 20178 yr by basatop

 all I can picture, are Eddy Currents everywhere...

12 minutes ago, ashkale said:

fluids flows from area of high pressure to low pressure - unfortunately the sea isnt accepting any more water and is at same or higher pressure than water in the river so this is just ridiculous. 

 

Sure glad you don't teach fluid mechanics...

 

Definitely havent been in teaching in Thailand as is evident!

35 minutes ago, noahvail said:

Axial flow pumps work very well because the impellers, or propellers, are housed within a pipe. They do not have to contend with dissipation into surrounding waters until the job is done and the pipe ends. It’s quite different from being immersed in pure liquid without a tube to direct the water.

 

True that boat props aren't very efficient axial flow pumps because of that.  But they do move water, as anyone who's ever opened up their boat's throttle when the boat was tied to the dock will attest.

 

And if boats is what you have laying around and purpose built pumps are hugely expensive, 6-12 months on delivery, and only needed a few days a year, you bring what you have.  Then when you're done, they go back to whatever they were doing.  Those economics alone are another calculation I haven't seen from anyone here on TVF.

 

Edited October 25, 20178 yr by impulse

I will sleep much better tonight knowing the Navy has the problem under control.

The Navy is headed to the Nan River. And yes the river is high. This is only the second time I have seen them in this area. The first time was the last coup.

5 hours ago, HooHaa said:

helpful or not the idea certainly has legs.

It may have legs but I could not run with it.

 

Maybe a good idea but probably nearly useless in practice. Flooded river, boats well upstream and I think the effect would cease within a few hundred metres.

 

But maybe if the boats were moored bank to bank?

7 minutes ago, lvr181 said:

It may have legs but I could not run with it.

 

Maybe a good idea but probably nearly useless in practice. Flooded river, boats well upstream and I think the effect would cease within a few hundred metres.

 

But maybe if the boats were moored bank to bank?

No one seems to have considered the displacement of the boats either- I'll get my coat.

How about forming a bucket line down to the sea?

 

 

 

Sorta like pissing into a hurricane init? Only problem is those making these useless descisions dont get the spray in the face.

On 10/24/2017 at 11:45 PM, phantomfiddler said:

According to the theory of Archimedes, the mere presence of the boats in the river is going to raise the water level. Eureka !!!

Phantomfiddler!   and Psimbo! you are wrong!Boats are on the river all the time,swimming up and down!You will not drop them from the Moon!?

They are there already...It has nothing  to do with Archimedes...   this is simple logic.Anyway - Bangkok is on sea level,you will not change  sea level even with 100000 boats.

Edited October 25, 20178 yr by basatop
correcta

How on earth can a propeller of a boat push huge volumes of water toward the sea,  Just want to be seen to be something. Futile attempt at flood control

12 hours ago, Dave67 said:

How on earth can a propeller of a boat push huge volumes of water toward the sea,  Just want to be seen to be something. Futile attempt at flood control

I seem to remember a few years ago it was suggested that helicopters flew upside down to clear the smog .  Some wag suggested at the time that the 'copter could mow his lawn at the same time.

Like to know the gallons of water pushed to gallons of fuel burnt? Once the water gets 100 ft from the boat it is going to slow down to the same speed of the rest of the water. Amazing Thailand. I guess they need to show the people that are getting flooded that they are doing something. 

2 minutes ago, pieeyed said:

Like to know the gallons of water pushed to gallons of fuel burnt? Once the water gets 100 ft from the boat it is going to slow down to the same speed of the rest of the water. Amazing Thailand. I guess they need to show the people that are getting flooded that they are doing something. 

Maybe it is more fuel efficient to use one of these.

Be cool to see them setting down between all the boats and barges. I guess dumping it down stream would make sense/

 

20 hours ago, Dave67 said:

How on earth can a propeller of a boat push huge volumes of water toward the sea,  Just want to be seen to be something. Futile attempt at flood control

As always with the Thai government intelligentsia they try to deal with the aftermath of the problem. Why not think laterally and fix the problem before it arises. They might be on the right track with propulsion of the water but they should start at the beginning of the problem rather than the end. I suggest the following:

 

1. Have high volume, high speed fans fitted onto trucks which could be mobilised in a hurry.

2. Send these trucks to areas where precipitation is anticipated and turn the fans skywards and turn up the power.

3. The strong winds would then blow the rain upward and back into the clouds which would then blow away and dissipate.

 

My suggestion makes about as much sense as their stupid idea of using boat propellers. Heaven forbid they might think it is a good idea...which wouldn't surprise me.

Thailand will be a developed country in 5 years with genius ideas like this. 

 

Perhaps they can get the Jetski operators to help from Pattaya.

12 minutes ago, Cadbury said:

As always with the Thai government intelligentsia they try to deal with the aftermath of the problem. Why not think laterally and fix the problem before it arises. They might be on the right track with propulsion of the water but they should start at the beginning of the problem rather than the end. I suggest the following:

 

1. Have high volume, high speed fans fitted onto trucks which could be mobilised in a hurry.

2. Send these trucks to areas where precipitation is anticipated and turn the fans skywards and turn up the power.

3. The strong winds would then blow the rain upward and back into the clouds which would then blow away and dissipate.

 

My suggestion makes about as much sense as their stupid idea of using boat propellers. Heaven forbid they might think it is a good idea...which wouldn't surprise me.

Or tie fans to the back of pigs so when they are at high altitude when flying they blow the rain clouds away.

Edited October 26, 20178 yr by wow64

Why not get all the little kiddies that are learning to swim to hang on a rope suspended over the bredth of the Chao Praya and practice their leg kicks in the direction of the flow of water. Every little bit helps....Could have teams of them. 

 What if they reinforce the "rain-making fleet" and modify these aircrafts?

 

  Phosphoric ideas in the Land of Smiles. 

 

     

 

  

Edited October 26, 20178 yr by jenny2017

Is it 1st April already?

 

I sincerely hope they don't seriously believe that this is going to make much/any difference, do they? 

 

A developed country in 20 years? More like in 2,000 years. 

Edited October 26, 20178 yr by djayz

Surely, any trivial increase in flow downstream would be offset by the cross-section of the boats obstructing the water level upstream? Oh, maybe so more water will go to those  monkey cheeks ......