Merged DDWFTTW in a “Real” Wind

[humber]

A simple proof that a balloon, released at above windspeed, will slow to below windspeed? I appear to have missed that. Perhaps you can direct me to where you posted it.

Did anyone else spot it?

Then you can't say you have been paying attention, nor even researched the matter at all.
But I did not ask for the wagons to form a circle, but if you would like Spork to demonstrate his claimed superior knowledge against little 'ol me.
Would you or not?

 

[humber]

Beware.


Crouching Humber, Hidden Woo.

Yo Mama Tambien
Feldspar?

ETA:
Wouldn't you like to see Spork defend his claim of WS balloons against me?
Why not?
A chance to justify that $40, and also gain what you really want?

 

[windgrins]

JBTD is totally on here!

I agree that cogent argument and not qualifications are relevant to the discussion we're having here, and I wouldn't expect anyone to parade their degrees to satisfy another's curiosity.

Yet there is an aspect in which it would be instructive to know the level at which some contributers are discussing the topics at hand. When a contributer implies he is considering a problem from a rarified level so advanced that it obviates any attempt to explain to this inexpert audience, yet simultaneously appears to have a grasp of related material which would embarrass a schoolchild, it certainly gives one pause.

As I said, I do not expect anyone to reveal their qualifications, I would merely observe that my experience, people who really understand a technical subject can generally describe its essence to a lay audience and answer their questions in language they can understand.

In violent agreement JBTD! I've seen some posts on this forum that would embarrass a brick!

Regards and well stated!

Windgrins

 

[Jack by the hedge]

Wait: Is this it, from way back on page 59?

How did it get there? Meteorologists in the field, use rule-of-thumb calculations. The force on the balloon is calculated according to Rayleigh's drag formula F = 1/2Cd.p.A(V^2). The force on balloon moving downwind is related to the relative speeds of balloon and wind so the force is
F = 1/2.Cd.p.A(Vwind - VBalloon)^2, but that is only half of the equation.

Newton says that F should be opposed by an equal force. That part of the equation is missing. That opposing force is not just due to the acceleration of the balloon, its inertia, F=ma, but drag components as the air flows over the balloon. Contact of the wind, with the balloon slows it, and it builds up in front of the balloon, as well as all sorts of parasitic drag effects. The balloon can never get to the state where (Vwind - VBalloon)^2. Simple as that.

Seriously though, is that it? I can kinda see your hands waving, and Newton spinning in his grave, but I can't see anything approaching a cogent argument for a balloon, released at above windspeed, slowing to below windspeed.

Can anyone else see it hidden in there?

 

[humber]

Wait: Is this it, from way back on page 59?

That is not what I asked you. And it is Spork who claims to be the aero expert
"top 1% of his field" he once claimed.

Ynot's questions and requests for tests have gone unheeded for years, as have so many others.

This balloon thing has been that same. No need to dredge the back-catalogue for this one. Right here and now.

Would you like to see Spork prove his claim of WS balloons against my proof that they don't?

 

[ThinAirDesigns]

"top 1% of his field" he once claimed.

Lie.

JB

 

[windgrins]

Humbers prolific posts

I agree. And at the same time I believe humber is lying about having any meaningful education.

I have no idea what his formal education in science is but....

Since we have what I would consider a valid sample set from his postings:

I believe Humber's posts are very indicative of Humber's understanding of this topic or of physics in general. I do believe that anyone reading his posts have adequate input to judge the merits or lacking's of his arguments to a satisfactory level.

I submit this simply a reflection of the concept that we make the bed that we lie in.

Windgrins

 

[humber]

In violent agreement JBTD! I've seen some posts on this forum that would embarrass a brick!

Regards and well stated!

Windgrins

Now you must be wanting to see that proof, Windgrins, after that remark.

Do you want to see Spork prove that WS balloon claim, against my proving the contrary?

It may be good to be assured that your Epiphany was not a blind date with
Timothy.

 

[humber]

I submit this simply a reflection of the concept that we make the bed that we lie in.

I think you may find one particular bed has suddenly become a bit damp.

 

[Jack by the hedge]

That is not what I asked you.

That's right. It's what I asked you. Remember? I asked you to justify your claim from waaaay back on page 58 that a balloon, released at greater than windspeed, would slow to below windspeed. And you can't, can you?

Would you like to see Spork prove his claim of WS balloons against my proof that they don't?

I frankly don't care. You may well have been too busy to notice, but I have studiously avoided getting dragged into the he said/he said artillery duel that's spread into this thread from elsewhere. I don't know Spork except by his reputation and he certainly doesn't know me.

What I want is for you to justify your declaration that a balloon, released at above windspeed, would slow to less than windspeed.

Are you going to try?

 

[windgrins]

Humber, please continue

Now you must be wanting to see that proof, Windgrins, after that remark.

Do you want to see Spork prove that WS balloon claim, against my proving the contrary?

It may be good to be assured that your Epiphany was not a blind date with
Timothy.

Humber,

I would like to see you show that balloons do not travel at wind speed after sufficient time to settle into a steady state--just for a little specificity, say 30 secs. I have not witnessed any thing that I would consider a proof or even a hint that balloons travel at less or more than windspeed in a steady state wind.

I also would still like to see your "Top Secret" cart performing as advertised with the listed stipulations. I'll toast you on your cleverness when we see it.

Windgrins

 

[humber]

Humber,

I would like to see you show that balloons do not travel at wind speed after sufficient time to settle into a steady state--just for a little specificity, say 30 secs. I have not witnessed any thing that I would consider a proof or even a hint that balloons travel at less or more than windspeed in a steady state wind.

I have, but it was a simple one. I can do much better than that.

Spork must disagree with my math. He claims that he don't need them there textbooks, so it should be an easy task for him to prove that I am wrong in the manner one would expect of an aero graduate; specifically mathematically.
He has never done that, Surprising, but true. Surely you would like to see that proof for yourself, Windgrins? To study and learn from? For the edification of all this thread's followers?

I also would still like to see your "Top Secret" cart performing as advertised with the listed stipulations. I'll toast you on your cleverness when we see it.

You will, and it won't be cleverness that gets well and truly toasted.

 

[windgrins]

I have, but it was a simple one. I can do much better than that.

Spork must disagree with my math. He claims that he don't need them there textbooks, so it should be an easy task for him to prove that I am wrong in the manner one would expect of an aero graduate; specifically mathematically.
He has never done that, Surprising, but true. Surely you would like to see that proof for yourself, Windgrins? To study and learn from? For the edification of all this thread's followers?

Humber,

Since you politely asked, I will give you my opinion:

I believe (and I think that Spork believes-but I do not want to speak for him) that Inertial Reference Frames (IRF) are a valid concept from physics. There are subtleties associated with taking a ground frame as an IRF but for the purpose of these discussions, it is a reasonable choice with minor error.

I think an impermeable floating balloon (very very slightly buoyant) tethered by a loose string in a sealed stationary box (wrt ground) and with stable temps, will not move-other than perhaps to experience a Foucault pendulum effect on a daily basis, that this demonstrates that a balloon in a steady state wind will move at the speed of the wind. (Incidentally, the daily spinning of the balloon due to the Foucault pendulum effect is one of the minor errors to which I refer.) I also believe that this produces a falsifiable (and in this case testable) claim that could be reasonably verified by putting a balloon in a box for a week and taking an hourly time lapse photo of it. I don't however intend to conduct this experiment but anyone else should feel free to because it is pretty simple.

I know you have issues with IRFs so I'm not asking you to accept this but for me it is sufficient. Therefore, I would like to see you justify your belief with the above rigor.

I would politely ask also that other posters feel free to comment on my argument from above. I'm OK with feedback here and there may be something I'm missing.

Regards,

WindGrins

 

[spork]

I believe (and I think that Spork believes-but I do not want to speak for him) that Inertial Reference Frames (IRF) are a valid concept from physics. There are subtleties associated with taking a ground frame as an IRF but for the purpose of these discussions, it is a reasonable choice with minor error.

I think an impermeable floating balloon (very very slightly buoyant) tethered by a loose string in a sealed stationary box (wrt ground) and with stable temps, will not move-other than perhaps to experience a Foucault pendulum effect on a daily basis, that this demonstrates that a balloon in a steady state wind will move at the speed of the wind. (Incidentally, the daily spinning of the balloon due to the Foucault pendulum effect is one of the minor errors to which I refer.) I also believe that this produces a falsifiable (and in this case testable) claim that could be reasonably verified by putting a balloon in a box for a week and taking an hourly time lapse photo of it. I don't however intend to conduct this experiment but anyone else should feel free to because it is pretty simple.

I know you have issues with IRFs so I'm not asking you to accept this but for me it is sufficient. Therefore, I would like to see you justify your belief with the above rigor.

Perfectly reasonable - and infinitely beyond humber's ability to understand.

Yes he will search Wikipedia for Foucault Pendulum, find some irrelevant facts to post, and use it to make exactly the opposite of the point he wishes to make (namely that he has a clue). But the reality is that he doesn't understand the most basic aspects of your proof. The above is a fine exercise, but any notion that you might convince humber of anything, through any means, is misplaced.

 

[humber]

I have, but it was a simple one. I can do much better than that.

Spork must disagree with my math. He claims that he don't need them there textbooks, so it should be an easy task for him to prove that I am wrong in the manner one would expect of an aero graduate; specifically mathematically.
He has never done that, Surprising, but true. Surely you would like to see that proof for yourself, Windgrins? To study and learn from? For the edification of all this thread's followers?

Humber,

Since you politely asked, I will give you my opinion:

I believe (and I think that Spork believes-but I do not want to speak for him) that Inertial Reference Frames (IRF) are a valid concept from physics. There are subtleties associated with taking a ground frame as an IRF but for the purpose of these discussions, it is a reasonable choice with minor error.

I say that use of inertial frames is bogus, Windgrins. There are no asymmetries of frame, so any "subtleties" will be the result of using an over-simplified model of the world.

I think an impermeable floating balloon tethered by a loose string in a sealed stationary box (wrt ground) and with stable temps, will not move-other than perhaps to experience a Foucault pendulum effect on a daily basis, that this demonstrates that a balloon in a steady state wind will move at the speed of the wind.

Wind tunnels are an example of the practical use of Galilean Relativity.
Does that mean that when the control for the airspeed of the fan of wind tunnel been turned off, the dial reads 0m/s or "windspeed"?

And that was not the question. Do balloons travel at windspeed?

I know you have issues with IRFs so I'm not asking you to accept this but for me it is sufficient. Therefore, I would like to see you justify your belief with the above rigor.

I have no trouble with FOR, Windgrins. How hard is it to understand physics naiveté?

Ask uncool. He said that I did not understand, so I posted a transform of a metal plate moving at 10m/s wrt the floor. Taking the average molecular speed to be 500m/s, and its momentum, I calculated the KE transfer on each side of the plate, relative to the plate, and relative to the ground.
Would you like to see it?

I would politely ask also that other posters feel free to comment on my argument from above. I'm OK with feedback here and there may be something I'm missing.
Regards,
WindGrins

It's nice to have a stance of scientific integrity, Windgrins, but another to actually support it.

Would you like to see Spork prove or defend his claim of WS balloons against me? It will be inadequate to simply assert simple models, without showing mathematically where my contradicting fluid dynamics calculations are wrong.
Now you may say that FOR is taught and accepted, but if that is true, students of aerofynamics also get a large slice of fluid dynamics, like it or not.

 

[humber]

Perfectly reasonable - and infinitely beyond humber's ability to understand.

Yes he will search Wikipedia for Foucault Pendulum, find some irrelevant facts to post, and use it to make exactly the opposite of the point he wishes to make (namely that he has a clue). But the reality is that he doesn't understand the most basic aspects of your proof. The above is a fine exercise, but any notion that you might convince humber of anything, through any means, is misplaced.

You said that I had no qualifications.
And this
Perfectly reasonable - and infinitely beyond humber's ability to understand.
BTW: read about the pendulum in a childhood science book.

I am challenging you to prove that you have the qualifications and skill to demonstrate your knowledge of fluid dynamics against me, where the topic is balloons and wind speed. This forum, right here, Spork.

You gave Ynot a chase, so are we to see a repeat performance, or are you going to live up to your boasts and claims?

So, which way will it be this time?

With such a long thread, we need a fresh one, so links don't get lost or posts searched for.
This one will be indelibly bookmarked, Spork.

 

[windgrins]

Perfectly reasonable - and infinitely beyond humber's ability to understand.

Yes he will search Wikipedia for Foucault Pendulum, find some irrelevant facts to post, and use it to make exactly the opposite of the point he wishes to make (namely that he has a clue). But the reality is that he doesn't understand the most basic aspects of your proof. The above is a fine exercise, but any notion that you might convince humber of anything, through any means, is misplaced.

Thanks for the fine comment Spork. I'm not suffering from any such delusions. He asked a reasonable question and I answered politely and I hope, concisely.

Regards,

WindGrins

 

[humber]

Thanks for the fine comment Spork. I'm not suffering from any such delusions. He asked a reasonable question and I answered politely and I hope, concisely.

Regards,

WindGrins

And evaded one. I don't expect to have to tell a reasonable person which one I am referring to, Windgrins.

 

[windgrins]

Humber-answers to the questions that I follow.

Humber in blue:

Wind tunnels are an example of the practical use of Galilean Relativity.
Does that mean that when the control for the airspeed of the fan of wind tunnel been turned off, the dial reads 0m/s or "windspeed"?

For a balloon traveling at windspeed, that would work just fine. If you want to study anything in a windtunnel traveling at windspeed over a long period of time, that is the only practical way I see of doing it. I haven't actually looked closely at a wind tunnels "Off" position when I was at my last wind tunnel but I suppose for any aerodynamicist it would be reasonable to label the control as 0m/s or Windspeed, but most likely "OFF".

And that was not the question. Do balloons travel at windspeed?

The short answer is "Yes"

The long answer is "After a reasonable time (more than 10 sec but less than 1 minute) to allow the wind to overcome the balloons inertia down to the level of molecular motion, Yes."

Would you like to see Spork prove or defend his claim of WS balloons against me? It will be inadequate to simply assert simple models, without showing mathematically where my contradicting fluid dynamics calculations are wrong.

I certainly would not bother if I were in Spork's shoes! Spork is free to do as he pleases!

Regards,

WindGrins

 

[humber]

Humber in blue:

Wind tunnels are an example of the practical use of Galilean Relativity.
Does that mean that when the control for the airspeed of the fan of wind tunnel been turned off, the dial reads 0m/s or "windspeed"?

For a balloon traveling at windspeed, that would work just fine. If you want to study anything in a windtunnel traveling at windspeed over a long period of time, that is the only practical way I see of doing it.

Let me see. A missile is traveling at the speed of wind to the right. The wind is 600mph wrt ground. Another is traveling at the speed of the wind, but the other way to the left: - 600mph relative to the ground. Do you think that when they collide, that can be simulated by two missiles on the ground rubbing noses? What if the downwind one is stationary, and the other hits it as 600mph?

ETA:
What about a big and massive balloon? It is traveling downwind at windspeed. A bird moves towards it at 1mph relative to the balloon. If a WS balloon can be said to be like a balloon in a room, then coaxing the bird towards the balloon should be the same thing.
Galilean Relativity does not allow velocity to be arbitrarily dispensed with.

And that was not the question. Do balloons travel at windspeed?
The short answer is "Yes"

The long answer is "After a reasonable time (more than 10 sec but less than 1 minute) to allow the wind to overcome the balloons inertia down to the level of molecular motion, Yes."

And how go you overcome the boundary layer?

Would you like to see Spork prove or defend his claim of WS balloons against me? It will be inadequate to simply assert simple models, without showing mathematically where my contradicting fluid dynamics calculations are wrong.

I certainly would not bother if I were in Spork's shoes! Spork is free to do as he pleases!
Regards,

I did not ask you about Spork, but would you like to see him prove that balloons travel at windspeed ?

Frames of reference in no way contradict fluid dynamics, so there must be common ground. You have suggested that the Coriolis effect will be a minor difference, so I think that implies there may be larger ones to deal with at some stage.
You have posted that qualifications do not matter, and that only the quality of the arguments counts, and you will asses them on that basis.

So do you want to see that proof presented here?