Tugboats Harnessed To Tackle Raging Floodwaters

[shriah]

This is one of the font page article in Bangkok Post .

Is it really possible to increase the velocity of river flow with boats tied to a bridge ? The article claims that 8 boats running all day was able to increase the flow of river by 20% or 57 cubic metres a second .

Edited September 20, 2011 by lopburi3
remove link per forum rules

[Soutpeel]

.......

[gennisis]

I suppose that if the boats were moored in a line between the bridge piers then the open river surface would be less and the same river flow would then increase at the surface and to a depth of the boats

But soon after the bridge the flow would go back to its normal flowrate.

[TheWalkingMan]

:lol:

Even with my limited physics education... I say that it is not possible. The increase in flow near the tug boats would dissipate pretty quick and essentially be absorbed by the volume of the river.

[OccamsRazor]

I think Venturi and Bernoulli might have something to say about that. It will increase at the point of contact and very quickly back to norm after passing as the pressures re-equalize. Think aircraft wing.

[kartman]

I think the only flow will be into someones pocket somehow somwhere.

[bkkjames]

I give them an f for effort. Lol

[canuckamuck]

Nature's laws were made to be broken

[StreetCowboy]

I wonder how the jet fans in tunnels work?

SC

[Semper]

Thai wisdom.

[Dag]

There is a report that they are using the floodwater floating barriers to tow large amounts of water downstream and into the oceans.

[dominique355]

I wonder how the jet fans in tunnels work?

SC

Maybe because air is compressible and water isn't.

It seems to me that these boat propeller probably increase the waterflow right behind them by increasing the height of the water. So most of the energy goes into lifting the water and will quickly be neutralized when it comes down to the previous level. Some of the energy would probably go into increasing the motion (speed) of water, but there is a huge amount of inertia. So probably in the result some of the propeller energy will increase the speed of the water in the river, but not much. Most energy will be wasted.

[PoorSucker]

Some politicians own tugboats?

[WarpSpeed]

I think Venturi and Bernoulli might have something to say about that. It will increase at the point of contact and very quickly back to norm after passing as the pressures re-equalize. Think aircraft wing.

JFYI has anyone ever heard of pumping stations? They operate on precisely this principle.

If you increase volume by increasing flow rate you then increase flow rate downstream by sheer increase in water volume created after the point of the boats being moored which will in turn increase flow rate and volume. However I see this as exasperating the problem beyond that point and increasing the water volume which will then increase flooding.. But in theory it can and will have an effect of increasing flow rate..

Edited September 21, 2011 by WarpSpeed

[WarpSpeed]

I wonder how the jet fans in tunnels work?

SC

As pumping stations..

[WarpSpeed]

I wonder how the jet fans in tunnels work?

SC

Maybe because air is compressible and water isn't.

It seems to me that these boat propeller probably increase the waterflow right behind them by increasing the height of the water. So most of the energy goes into lifting the water and will quickly be neutralized when it comes down to the previous level. Some of the energy would probably go into increasing the motion (speed) of water, but there is a huge amount of inertia. So probably in the result some of the propeller energy will increase the speed of the water in the river, but not much. Most energy will be wasted.

Not completely true, water is slightly compressible but that's being pedantic and it doesn't apply to the principle being applied nor to Cowboys post.. Actually it's because water is less compressible that it can work as it will be less reactive to a compressing effect like propellers moving water instead of compressing once it has passed the point of pumping it then expands less but rather increases flow rate and volume. Sorry to say but the Thai's have a possibly clever way to reduce the time of flooding kudos to them..

JFYI the thread isn't about energy efficiency but about moving high volumes of water more expediently so lets not get sidetracked from the original purpose of the tugs..

Edited September 21, 2011 by WarpSpeed

[WarpSpeed]

^^^ Post #14 Correct to "exacerbating" not "exasperating" though they both work...

[Chonburiram]

I think hydro mechanic is too difficult for most Thais/Thaivisa members ( except Herr Dr. "Naam" ) to understand... Maybe they should clear all rivers from everything that floats to bring the water level down?

[WarpSpeed]

Sorry bud I ain't one of em but you certainly may be depending on what the code in your post actually means?? ...

Edited September 21, 2011 by WarpSpeed

[kurnell]

I think this works only in Bugs Bunny cartoons

[WarpSpeed]

I think this works only in Bugs Bunny cartoons

So I guess by that you don't understand fluid dynamics, flow rates versus water volume either then do you ?

Instead why don't you google up "pumping stations" ?

Edited September 21, 2011 by WarpSpeed

[krading]

I think this works only in Bugs Bunny cartoons

So I guess by that you don't understand fluid dynamics, flow rates versus water volume either then do you ?

Instead why don't you google up "pumping stations" ?

In a pipe where pressure can be generated, ok

but in an open river system?

Now, where did I leave my Acme Tidal Wave Generator?

Edited September 21, 2011 by krading

[kurnell]

I think this works only in Bugs Bunny cartoons

So I guess by that you don't understand fluid dynamics, flow rates versus water volume either then do you ?

Instead why don't you google up "pumping stations" ?

I understand that an enormous earthquake can displace huge amounts of water and send a tsunami to the other side of the planet, but half a dozen tug boats tied to a bridge is not going to increase flow by 20%. That is absurd. More like 0.00000002%. Perhaps you can Google examples of this being done somewhere else in the world

[WarpSpeed]

I think this works only in Bugs Bunny cartoons

So I guess by that you don't understand fluid dynamics, flow rates versus water volume either then do you ?

Instead why don't you google up "pumping stations" ?

In a pipe where pressure can be generated, ok

but in an open river system?

Now, where did I leave my Acme Tidal Wave Generator?

Fluid dynamics apply in ALL instances whether a river or a pipe they are both conduits to move water and the river acts EXACTLY like a pipe only on a larger scale, if that's not beyond your comprehension to grasp?..

Let me just add that, as a smaller scale experiment so you can see the relativity. If you have a back yard pool of any length with properly located wall returns turn your tiny little pump and watch how quickly it begins to move the entire volume of your pool in the direction the returns point. It happens very quickly and is an exactly relative small scale version of this process..

Those returns are usually only fixed inches below the surface and are inches in diameter but have a dramatic effect on the entire flow from top to bottom and if you shut off the pool it will slow just as quickly..

Edited September 21, 2011 by WarpSpeed

[WarpSpeed]

I think this works only in Bugs Bunny cartoons

So I guess by that you don't understand fluid dynamics, flow rates versus water volume either then do you ?

Instead why don't you google up "pumping stations" ?

I understand that an enormous earthquake can displace huge amounts of water and send a tsunami to the other side of the planet, but half a dozen tug boats tied to a bridge is not going to increase flow by 20%. That is absurd. More like 0.00000002%. Perhaps you can Google examples of this being done somewhere else in the world

Just because it hasn't been done (and that doesn't mean it hasn't just means you in your limited experience doesn't know of any instances) doesn't mean it isn't feasible and I'm not the one foolishly questioning it's viability without the knowledge to understand what is being applied so you do your own home work for your own personal edification..

I tell you again to google pumping stations and there you will find that it not only has been done in other applications but it has been done for centuries..

Edited September 21, 2011 by WarpSpeed

[WarpSpeed]

How about this simple test while it's air and not water the test still applies, sit in front of a fan do you feel more air then with it not running? Simple isn't it?

I'd also like to know how much water do these tugs push in 24 hours at maximum throttle? These are rhetorical questions for me by the way designed to make you think before you post more uninformed tripe..

Tugs have massive propellers and huge diesels designed for pushing torque so they push millions of gallons per hour..

Some links for YOUR education..

Tug boats and pulling capacity

Bollard pulling strength

Note that these measurements are stated in "tons of pulling power" and the article does not state what HP nor bollard pulling capacity these tugs have but suffice it to say that any tugs WILL make a difference..

How much water do you think has to be moved to measure tons of power?

Edited September 21, 2011 by WarpSpeed

[WarpSpeed]

For optimum effectiveness though the tugs should be positioned just prior to the mouth of the river so as not to flood property down stream of their current location as the volume of water being pushed rises the river even more in that area.

[oldsailor35]

Of course this will work, provided the tugboat captains all wear the appropiately blessed amulets.

[oldsailor35]

I think this works only in Bugs Bunny cartoons

So I guess by that you don't understand fluid dynamics, flow rates versus water volume either then do you ?

Instead why don't you google up "pumping stations" ?

In a pipe where pressure can be generated, ok

but in an open river system?

Now, where did I leave my Acme Tidal Wave Generator?

Fluid dynamics apply in ALL instances whether a river or a pipe they are both conduits to move water and the river acts EXACTLY like a pipe only on a larger scale, if that's not beyond your comprehension to grasp?..

Let me just add that, as a smaller scale experiment so you can see the relativity. If you have a back yard pool of any length with properly located wall returns turn your tiny little pump and watch how quickly it begins to move the entire volume of your pool in the direction the returns point. It happens very quickly and is an exactly relative small scale version of this process..

Those returns are usually only fixed inches below the surface and are inches in diameter but have a dramatic effect on the entire flow from top to bottom and if you shut off the pool it will slow just as quickly..

The confined space of a pipe will not allow the water flow to disperse in any other way than away from the propeller. Whereas in the river it will go anywhere to the least resistance.

[Mirth]

How fast a water flows depends on the outlet. Generating pressure at midpoint would just increase pressure which would dissipiate somewhere down the line and not the end point. As 1 poster mentioned, it would just increase the volume or flood the area downstream but once the engine stops running, the flow will be back the same. Dredging would be a better solution. Multiple dredgers working simultaneously at different point of the river would give a better and long term solution.