Entrained Water Question!!!

[strantor]

I'm not following what you just described 100% but it sounds like you deviated from the scientific method and devised an experiment and complementary test metric designed to yield the results you wanted. Confirm bias at its worst.

Further it sounds like you are basing your conclusion on the absence of data that refutes your theory rather than the presence of data that confirms it. There's a name for that fallacy that I've forgotten.

In any case, it's obvious at this point (actually prior to this point) that your mind is made up on the matter and no amount of evidence to the contrary will dissuade you. I'm fine with that. You're "investigating " this in a professional capacity. Go ahead and try to pass this pseudoscience off to your peers. Nature will take its course and you'll learn the hard way. Heck maybe your peers will even fall for it, and you'll go about designing something around this failed concept with other people's money. Then you'll learn the even harder way.

I could easily perform the experiment myself and refute yours, but easier still, I could just send you the 47c I promised and watch in amusement. You'll need the cash anyway, going the direction you're headed. PM me your email and send you your money as promised.

 

[Tony Stewart]

Dear Iawia,
It would have been clearer to define a test from the beginning with all your assumptions. It wasn't even clear why CG was mentioned for a 1D static problem unless you wanted to make it a 2D or 3D problem and then make it dynamic because the vector forces of static vs dynamic vs linear vs rotational are completely different..

 

[Iawia]

I'm not following what you just described 100% but it sounds like you deviated from the scientific method and devised an experiment and complementary test metric designed to yield the results you wanted. Confirm bias at its worst.

Further it sounds like you are basing your conclusion on the absence of data that refutes your theory rather than the presence of data that confirms it. There's a name for that fallacy that I've forgotten.

In any case, it's obvious at this point (actually prior to this point) that your mind is made up on the matter and no amount of evidence to the contrary will dissuade you. I'm fine with that. You're "investigating " this in a professional capacity. Go ahead and try to pass this pseudoscience off to your peers. Nature will take its course and you'll learn the hard way. Heck maybe your peers will even fall for it, and you'll go about designing something around this failed concept with other people's money. Then you'll learn the even harder way.

I could easily perform the experiment myself and refute yours, but easier still, I could just send you the 47c I promised and watch in amusement. You'll need the cash anyway, going the direction you're headed. PM me your email and send you your money as promised.

Strantor, it is not clear why you are saying I am biased. I am not, actually. I designed the experiment to determine the location of CG. If a moment was produced, then CB and/or CG moved. If it did not rotate, then CB/CG is affected by entrained water (sealed or unsealed). You clearly do not understand physics and I don't have the time or patience to school you here. And your 'absence of data' comment is a bit ludicrous. What data is required exactly? The experiment was designed such that the assembly was long enough to produce a moment that is easily observed (1 lbf-in is a lot!). There is no need to gather data except with what is visually observable. If I want to determine if an object is red, a quick method would be to look at the object, rather than what you are alluding to is to setup a spectral analyzer of the reflected light. This is excessive, wastes too much time and money.

Your comments are a bit rude and unfounded, and I do not appreciate them.

Tony you are correct. I certainly should have stated my assumptions. I did not mention static or dynamic because it is not relevant purposes of the experiment. Although, static problems are clearly handled differently than dynamic ones, there are only two possible outcomes of the experiment. 1) When the seal is removed, no torque is produced hence no rotation occurs, hence CG/CB are affected by entrained masses. 2) The other result, torque is produced going from 0 to a non-zero number, and hence CG/CB are not effected by entrained mass (ie water within the holes of an object).

I am willing to hear others on this matter if you believe my experiment was biased or contained errors. But pls state exactly why from a scientific standpoint so that I may review it and carefully consider it conceptually and mathematically.

-t

 

[strantor]

Aww man; dislike points!? That'll teach me to waste my time with you again. I'll just take my elementary school comprehension of physics elsewhere...

 

[Iawia]

Below is scribbled my notes on how the experiment was conducted. It is still quite unclear how it is biased. If the system behaves one way, it indicates a conclusion. If it behaves another way, it indicates another. That's all. I admit I do had a particular belief that it would behave a certain way, but in no way did I allow that to affect the experimental design. You can decide for yourselves if this is a sufficient design.

My apologies for my grade school scratch paper. Not sure anyone was interested in the results.

 

[cowboybob]

Give it a shot. But before you do, consider this:

What is the flotation value, en-trained or not, of 20°C water IN 20°C water? Is it positively, negatively or neutrally buoyant?

 

[strantor]

You're going to give me a thumbs down again, but what the heck...

I should have more sense than try to argue with you, but I can't resist.

Assumption: If entrained water does not count toward CB or CG their locations will shift from their location (see locations in thest scenario #1)

WRONG. Why on earth would you make that assumption? That's exactly the opposite of what would happen.
It should read: If entrained water does count toward CB or CG then their locations will shift from their original location

Hence: if there is notable rotation then entrained masses (sealed and unsealed) DO NOT count toward CG and CB

WRONG. Once again, precisely the opposite.
Correction: Hence: if there is NO notable rotation then entrained masses (sealed and unsealed) DO NOT count toward CG and CB

If there is no rotation, then entrained masses (sealed and unsealed) DO count toward CG and CB

Correction: If there IS rotation, then entrained masses (sealed and unsealed) DO count toward CG and CB

CONCLUSION: WATER INSIDE OF HOLES IN PART DO COUNT TOWARD CB/CG LOCATIONS!!!

Correction: CONCLUSION: WATER INSIDE OF HOLES IN PART DO NOT COUNT TOWARD CB/CG LOCATIONS!!!

I'm not sure why you're still pushing this, going to the trouble of drawing out pictures when the concept is so obviously flawed. I'm even less certain about why I'm still debating it with you. I guess I'm just helplessly troll bait.

 

[cowboybob]

Me too...

My Grandfather loved, then my Father loved, and now I love, to hit myself on the head with a hammer because it feels sooo gooood when I stop .

Iawia, try this. A lot simpler:

Get and record the dry weight of a covered jar using a string around its neck attached to and hanging from a scale. Then fill the jar completely with water and secure the lid. Record that weight. With the full jar still attached to the scale, completely submerge the jar and record the weight. Remove the lid from the jar but leave it resting on the jar. Record that weight.

We'd be glad to explain the results.

 

[Iawia]

Me too...

Iawia, try this. A lot simpler:

Get and record the dry weight of a covered jar using a string around its neck attached to and hanging from a scale. Then fill the jar completely with water and secure the lid. Record that weight. With the full jar still attached to the scale, completely submerge the jar and record the weight. Remove the lid from the jar but leave it resting on the jar. Record that weight. On

We'd be glad to explain the results.

Lol you guys are funny. Rather than throwing insults on how I try and dupe my peers with foolish biased experiments, I'd much rather discuss how the system is flawed, why, and perhaps try and correct it. Cowboybob, as I have stated at least twice in this thread already, I am not concerned with weight, and it is not under debate . All of my peers agree with the dry and wet weights, and I have already done all the math to prove to myself that this is indeed the case: The weight of a submerged vessel filled with water and the weight of a submerged vessel with its lid unsealed weighs exactly the same.

You must pls try and cast aside notions of buoyancy and gravity centers because they do get screwy when parts are not symmetric and not in air! This is critical, we must just follow the math, and the actual behavior the pieces empirically. It appears that both of you are intelligent but you MUST do this in order to not be persuaded by an inaccurate assumptions. I know this is hard to do.

WRONG. Why on earth would you make that assumption? That's exactly the opposite of what would happen.
It should read: If entrained water does count toward CB or CG then their locations will shift from their original location

I suppose we should step back a second and define what this statement actually means. You are correct strantor, CB or CG would shift if their masses did count toward CB/CG locations. However, the opposite is also true, there would be a shift if they did not count, the question is SHIFT FROM WHERE? This is splitting hairs, so the conclusion I have come to is that entrained masses do indeed count toward CB/CG locations as stated in my conclusion on the scratch paper. My bad for the mix up.

WRONG. Once again, precisely the opposite.
Correction: Hence: if there is NO notable rotation then entrained masses (sealed and unsealed) DO NOT count toward CG and CB

Not sure where you are getting this quote from strantor but I say (see case 2 in the image middle of the page) the opposite. If I did say this somewhere else then I am incorrect. Consider case 1. The assembly is symmetric, and the string is centered over CB/CB. The vessels on each end are sealed. There will be no rotation because the force centers are on top of each other. case 2 NOW IF the vessel on the right becomes UNSEALED what happens to CB/CG? One school says (the one I subscribe too) nothing will happen, no rotation will occur because entrained mass (sealed or unsealed) will count toward CB/CG. IF IT DOES NOT COUNT, it will shift toward the left because that entrained mass no longer counts toward the weighted sum to compute CB/CG. CB/CG centers would no longer be atop of each other and would cause rotation. PLS explain why this you believe is not correct.

In any event, I have already performed the experiment and have determined that since there was no rotation, entrained water sealed or unsealed does count toward CB/CG, hence, all water in holes or features within the system's control volume must be counted toward CB/CG despite the fact that they do not weigh anything in water. If you are not convinced you should perform the experiment yourself. It is a fully unbiased experiment BTW.

Correction: CONCLUSION: WATER INSIDE OF HOLES IN PART DO NOT COUNT TOWARD CB/CG LOCATIONS!!!

Unfortunately, the opposite is true. I encourage you to perform the experiment yourself and perform the cb/cg locations by hand so you can see for yourself the truth about entrained masses.

Give it a shot. But before you do, consider this:

What is the flotation value, en-trained or not, of 20°C water IN 20°C water? Is it positively, negatively or neutrally buoyant?

Not sure why you are asking this, but I suppose I can answer it for you. Water underwater is technically weightless, as long as it has the same density of its surrounding environment. Thus, it is neutrally buoyant.

 

[strantor]

You are correct strantor, CB or CG would shift if their masses did count toward CB/CG locations. However, the opposite is also true, there would be a shift if they did not count

Ok, bro. I'm out.

 

[Iawia]

Ok, bro. I'm out.

Each one of your statements have been addressed. The explanation of a shifting of cb/cg i admit was a bit shaky and I can fully define it better if asked, but the conclusion still remains the same as stated in the images.

Is this what you do when someone takes you to task on 3 out of 3 complaints? Continue to reject knowledge strantor, you will not benefit from such behavior.

Have a good day, pls.

 

[cowboybob]

Is this what you do when someone takes you to task on 3 out of 3 complaints? Continue to reject knowledge strantor, you will not benefit from such behavior.

Perhaps you have proved, for yourself, your thesis. Or disproved it. Whatever. That does not make it "knowledge", in the general sense of the word.

It will become "knowledge" when you show us the math confirmation and that proof "holds water" (forgive me, I couldn't help myself).