DavidJames
Penultimate Amazing
If he does, I bet it will include a detailed technical description which would include one or more of the following engineering acronyms.
LOL, LMAO, LMFAO, ROTFLMAO
Fyziks 101
- Thread starter Turbofan
- Start date
LOL, LMAO, LMFAO, ROTFLMAO
Well, this thread has become just another rerun of the Truth Movement's Greatest Misses, and Turbofan's outbursts are borderline at best, so I won't be responding to him any further.
I just want to clean up one last, eye-opening pack of misinformation regarding basic physics, in case anyone should happen to read this and get confused. If, gentle reader, in the future you find yourself being swayed by this guy's arguments, keep in mind that his grasp of physics is almost completely wrong. The only person more ignorant would be Killtown, and that, maybe. So get a second opinion. Ask me, ask other posters here. If you don't trust us, talk to a physics professor. These mistakes are so fundamental, it won't take long to clear them up, and you may learn something in the process.
The total pressure is the sum of static and dynamic pressure. Dynamic pressure is calculated as ρ v2/ 2. See Bernoullli's Theorem for the complete explanation. This governs a lot of fluid motion behavior at reasonable speeds.
The static pressure inside the building and outside the building is the same before the collapse begins. Because there is no motion approaching the speed of sound -- at least early in the collapse -- there are no appreciable compressibility effects, and so the static pressure remains the same.
What changes, of course, is the dynamic pressure term. As the collapse gets underway, the air inside the structure is moving, pushed by falling floors. The air outside the structure doesn't move very much, since it has many more ways to get out of the way. This creates a rise in the dynamic pressure, but the static pressure stays the same.
As a result, the pressure inside exceeds the pressure outside. There is no "balance," and there is no "overcoming of the ambient pressure." The ambient pressure inside the structure is already enough to balance the ambient pressure outside. So any rise in the dynamic pressure means air leaves the structure. Just like you can use the Bernoulli equation to convert velocity to pressure, you can convert pressure back to velocity (for reasonable conditions).
This should not be counterintuitive. Of course the air will leave the structure. It's moving! It can't just stop moving unless there is something to oppose its dynamic pressure.
The argument Turbofan originally clung to was that the large holes in the structure would bleed away the pressure quickly. Well, no. If the pressure rise had been static, that would be true, because we would not have a sealed container or anything even close to it. In the case of dynamic pressure, however, the dynamic pressure only disappears when the fluid stops moving. This takes time. A larger hole means more air exits that side, and the greater air motion means more rapid dissipation, as the air's inertia is mixed with the outside air. But you still have the same dynamic pressure all over the place. Whatever the air's motion is, at any point, you can compute the dynamic pressure. And the air is moving even far away from the giant hole left by the aircraft.
If this was not the case, then things like ceiling fans wouldn't work at all. There's not just a "big hole" near a ceiling fan -- it's running practically in free space! So why doesn't the air just dodge the ceiling fan and stay at ambient pressure, moving basically nowhere? Or why does even merely waving your hand create a detectable breeze? Answer, because the air acquires inertia. That's what the dynamic pressure essentially is. The ceiling fan creates a substantial dynamic pressure on one side, and a negative dynamic pressure (though still positive total pressure) on the other side, and this means air motion, in this case air motion at a few meters per second. This doesn't just instantly dissipate. It can only do so through mixing, and so while a ceiling fan will not create a beam of moving air hundreds of meters long, it will create airflow several meters away. Even with no containment whatsoever. Even if operating in the open.
The situation in the Towers is vast by comparison. We have floor pans 4,000 square meters in size moving several meters per second, and with much better containment than a ceiling fan. Just because there's a hole on one side of the structure does not mean that there won't be air trying to escape in other places.
Besides Bernoulli, if we assume the air is incompressible (which is a reasonable simplification here), we can also solve for the fluid velocity through simple conservation of mass. We know how much mass is being pushed down by the upper block. This is the exact same mass that has to leave through whatever holes are available. Since the holes total a smaller area than the floor pans, the speed of the fluid is higher through the holes than it is at the face of the floor pans -- A1 v1 = A2 v2.
Energy, however, is not so easy to solve, because the floor pans are pushing the fluid, thus injecting energy into it. I had a lengthy discussion with Gregory Urich on this topic as it pertains to WTC 7, as seen in this thread. In posts such as this and this other one, I work with Gregory to even estimate the actual energy and heating experienced during the WTC 7 collapse. It's more than you might expect.
Turbofan, in essence, has provided us with the fluid equivalent of the "Net Force = 0" mistake made by other, equally ignorant Truth Movement bravos in the past. His insistence that the total pressure outside is equal to the total pressure inside is nonsense. Because the static pressures are the same, this is only true when the dynamic pressures are zero, i.e. velocity equals zero.
What we see from the video, instead, is a fairly high but still well subsonic fluid velocity. This velocity compares very nicely to what we compute with these methods, i.e. the "puffs" and "squibs" and so on are a perfect fit to simple air expellation as the collapse begins. It is in no way consistent with the supersonic bursts associated with explosives. Anyone with the faintest understanding of this subject would be daft to conclude otherwise.
This is why a grounding in elementary physics is useful. To my knowledge, there is not a single MIHOP hypothesis that cannot be discarded using basic physics alone. This is also why the Truth Movement has found it impossible to produce anything in support of itself that survives legitimate peer-review.
I just want to clean up one last, eye-opening pack of misinformation regarding basic physics, in case anyone should happen to read this and get confused. If, gentle reader, in the future you find yourself being swayed by this guy's arguments, keep in mind that his grasp of physics is almost completely wrong. The only person more ignorant would be Killtown, and that, maybe. So get a second opinion. Ask me, ask other posters here. If you don't trust us, talk to a physics professor. These mistakes are so fundamental, it won't take long to clear them up, and you may learn something in the process.
The total pressure is the sum of static and dynamic pressure. Dynamic pressure is calculated as ρ v2/ 2. See Bernoullli's Theorem for the complete explanation. This governs a lot of fluid motion behavior at reasonable speeds.
The static pressure inside the building and outside the building is the same before the collapse begins. Because there is no motion approaching the speed of sound -- at least early in the collapse -- there are no appreciable compressibility effects, and so the static pressure remains the same.
What changes, of course, is the dynamic pressure term. As the collapse gets underway, the air inside the structure is moving, pushed by falling floors. The air outside the structure doesn't move very much, since it has many more ways to get out of the way. This creates a rise in the dynamic pressure, but the static pressure stays the same.
As a result, the pressure inside exceeds the pressure outside. There is no "balance," and there is no "overcoming of the ambient pressure." The ambient pressure inside the structure is already enough to balance the ambient pressure outside. So any rise in the dynamic pressure means air leaves the structure. Just like you can use the Bernoulli equation to convert velocity to pressure, you can convert pressure back to velocity (for reasonable conditions).
This should not be counterintuitive. Of course the air will leave the structure. It's moving! It can't just stop moving unless there is something to oppose its dynamic pressure.
The argument Turbofan originally clung to was that the large holes in the structure would bleed away the pressure quickly. Well, no. If the pressure rise had been static, that would be true, because we would not have a sealed container or anything even close to it. In the case of dynamic pressure, however, the dynamic pressure only disappears when the fluid stops moving. This takes time. A larger hole means more air exits that side, and the greater air motion means more rapid dissipation, as the air's inertia is mixed with the outside air. But you still have the same dynamic pressure all over the place. Whatever the air's motion is, at any point, you can compute the dynamic pressure. And the air is moving even far away from the giant hole left by the aircraft.
If this was not the case, then things like ceiling fans wouldn't work at all. There's not just a "big hole" near a ceiling fan -- it's running practically in free space! So why doesn't the air just dodge the ceiling fan and stay at ambient pressure, moving basically nowhere? Or why does even merely waving your hand create a detectable breeze? Answer, because the air acquires inertia. That's what the dynamic pressure essentially is. The ceiling fan creates a substantial dynamic pressure on one side, and a negative dynamic pressure (though still positive total pressure) on the other side, and this means air motion, in this case air motion at a few meters per second. This doesn't just instantly dissipate. It can only do so through mixing, and so while a ceiling fan will not create a beam of moving air hundreds of meters long, it will create airflow several meters away. Even with no containment whatsoever. Even if operating in the open.
The situation in the Towers is vast by comparison. We have floor pans 4,000 square meters in size moving several meters per second, and with much better containment than a ceiling fan. Just because there's a hole on one side of the structure does not mean that there won't be air trying to escape in other places.
Besides Bernoulli, if we assume the air is incompressible (which is a reasonable simplification here), we can also solve for the fluid velocity through simple conservation of mass. We know how much mass is being pushed down by the upper block. This is the exact same mass that has to leave through whatever holes are available. Since the holes total a smaller area than the floor pans, the speed of the fluid is higher through the holes than it is at the face of the floor pans -- A1 v1 = A2 v2.
Energy, however, is not so easy to solve, because the floor pans are pushing the fluid, thus injecting energy into it. I had a lengthy discussion with Gregory Urich on this topic as it pertains to WTC 7, as seen in this thread. In posts such as this and this other one, I work with Gregory to even estimate the actual energy and heating experienced during the WTC 7 collapse. It's more than you might expect.
Turbofan, in essence, has provided us with the fluid equivalent of the "Net Force = 0" mistake made by other, equally ignorant Truth Movement bravos in the past. His insistence that the total pressure outside is equal to the total pressure inside is nonsense. Because the static pressures are the same, this is only true when the dynamic pressures are zero, i.e. velocity equals zero.
What we see from the video, instead, is a fairly high but still well subsonic fluid velocity. This velocity compares very nicely to what we compute with these methods, i.e. the "puffs" and "squibs" and so on are a perfect fit to simple air expellation as the collapse begins. It is in no way consistent with the supersonic bursts associated with explosives. Anyone with the faintest understanding of this subject would be daft to conclude otherwise.
This is why a grounding in elementary physics is useful. To my knowledge, there is not a single MIHOP hypothesis that cannot be discarded using basic physics alone. This is also why the Truth Movement has found it impossible to produce anything in support of itself that survives legitimate peer-review.
LashL
Goddess of Legaltainment™
- Joined
- Aug 12, 2006
- Messages
- 36,711
Quite aside from R.Mackey's excellent and more than sufficient smackdown above, Turbofan's lame appeal to the false, entirely unfounded, and entirely unsupported "authority" of the likes of David Griffin and Kevin Ryan just cracked me up, so I couldn't resist adding this:
rwguinn
Penultimate Amazing
mumble mumble
goalposts.. goalposts ..mumble know they were here...
Are we in the stadium yet?
are we playing Football, soccer, Australian football, or baseball? Just whereinhell are we headed, here?
goalposts.. goalposts ..mumble know they were here...
Are we in the stadium yet?
are we playing Football, soccer, Australian football, or baseball? Just whereinhell are we headed, here?
Disbelief
Illuminator
- Joined
- Mar 27, 2007
- Messages
- 3,606
So, 50% greater time and you don't see anything wrong with saying "near freefall?" So if someone wanted to pay you $150,000, would you say you would take $100,000 because it is near enough?
You are saying the exact same thing I said with a bunch of smoke and mirrors
around it!
If the static pressure is equal inside and outside the building, then the
rise in dynamic pressure causes the flow to move from inside the building
to outside the building (overcoming only ambient pressure).
Or in other words; there was no appreciable dynamic pressure outside of the
large airplane hole to prevent the dynamic pressure build to escape unimpeded.
Ding, ding!
How fast did we calculate the building to be moving within the first second?
No more than 9.8 m/s correct? (Notice everyone, that's speed, not acceleration
)Ding, ding! Like I mentioned before: Without pressure differential, you cannot
have flow.
So then, please explain to me (and the others), how you get a jet of debris
from one side of the floor, if the giant hole exists on the other side which
would experience the same dynamic pressure?
phunk
Illuminator
- Joined
- Aug 10, 2007
- Messages
- 4,127
So then, please explain to me (and the others), how you get a jet of debris
from one side of the floor, if the giant hole exists on the other side which
would experience the same dynamic pressure?
It's simple. The dynamic pressure doesn't look for the biggest opening and only go that way. It goes out through ALL of the openings. That includes flowing down through the core to lower levels.
Oh, I see. Soooo...it has all of that volume to displace itself, yet it just
wants to jet out one way?
nicepants
Graduate Poster
- Joined
- Jan 8, 2007
- Messages
- 1,723
So then, please explain to me (and the others), how you get a jet of debris
from one side of the floor, if the giant hole exists on the other side which
would experience the same dynamic pressure?
It goes back to that whole "path of least resistance" thing that you truthers never seem to understand.
ETA:
Oh, I see. Soooo...it has all of that volume to displace itself, yet it just
wants to jet out one way?
It's not that it "just wants to jet out one way"...it's trying to equalize wherever it can. What part of "It goes out through ALL of the openings." was unclear to you?
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rwguinn
Penultimate Amazing
You mean that the far-off person you're yelling to has a greater chance of hearing you yell if you're facing his direction instead of away from him?
Imagine that!
Oh, I see. Soooo...it has all of that volume to displace itself, yet it just
wants to jet out one way?
How on earth did you get "just wants to jet out one way" from reading "goes out through ALL the openings"?
Perhaps you learned this technique of deliberate incomprehension from George W. Bush, who has often used it to distort opponents' viewpoints and interviewers' critical questions to his advantage.
If it's any less disgusting when you do it than when your role model Dubya does, it's only because your views are far less consequential.
Respectfully,
Myriad
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It goes back to that whole "path of least resistance" thing that you truthers never seem to understand.
You mean, a hole the size of an airplane has more resistance than a window?
Are you sure you know what you're talking about?
You are telling me that the air is going to build pressure against the window
and 'jet' out before it equalizes the volume adjacent?
I wont bet on it, but I'd think even Mr. Mackey will have trouble with your
post.
Explain how to produce a jet of debris out the side of the building, when
you have an airplane sized hole on the same floor.
Use this diagram to explain your answer:
http://www.procision-auto.com/Tino/911_pressure.jpg
Just to clarify, you are saying the pressure will build only on the right side
of the floor, and blow out the window...before it exits the large opening
on the left?
That is not the path of least resistance!
Where is the big airplane sized jet of debris then?
I love the guess work going on with you guys. Keep adding to your theory
until something makes a bit of sense.
funk de fino
Dreaming of unicorns
That is not the path of least resistance!
Where is the big airplane sized jet of debris then?
I love the guess work going on with you guys. Keep adding to your theory
until something makes a bit of sense.
seen as you continue to avoid post # 500
Were all the floors in the building open plan TF? If not what would this have done to the air pressure inside the building on various floors?
If you have a room on that floor that is shut off from the rest of the floor then the pressure in that room has no way of reaching the open hole on the other side of the building so it will follow the path of least resistance and blow out the window of that room. Correct?
RE:#500
It doesn't account for the core columns. It doesn't account for the mass
that is blowing apart before the support structure descends. I've already
posted this pages ago!
I guess the plane didn't knock down any of those "walls" huh?
It doesn't account for the core columns. It doesn't account for the mass
that is blowing apart before the support structure descends. I've already
posted this pages ago!
I guess the plane didn't knock down any of those "walls" huh?
funk de fino
Dreaming of unicorns
It does not have to because the core remained standing after the floors gave way. I knew you would be unable to disprove it. After claiming the explanation did not even exist, you then fail to understand it.
The mass is not blowing apart. The floor above dropping on the floors below overloaded the design static loads for the floor therefore the floor connections failed. Once these failed the core and perimiter columns could no longer stand. It is all available to see and hear in videos. Unlike the demolition charges the truther bots claim blew the building apart.
Please explain why the floor connections would have held?
TF said:I guess the plane didn't knock down any of those "walls" huh?
Speculation? Some truthers reckon the plane debris did not reach far enough to damage the cores so why would they have reached the other side of the building. Even if they could would the cores not stop debri from reaching them? Were the toilets and offices in the floors all open plan? If not then this explains differences in pressure and paths in the building for the air during collapse.
Please explain why this is not so?
Really? Then what force broke that core apart? I would obviously need
some sort large mass to squish it down vertically within seconds!
Right...300 ft of tower is missing before the support structure descends.
It's clearly shown in the video, and still frame photos linked in the first post.
Because of the 47 core columns, and 230+ perimeter columns.
The pancake theory was debunked long ago my friend. Start catching up
to the new NIST excuse.
Well, who are you going to believe? The truthers, or NIST? NIST says some
of the core columns were damaged. I guess we're at least mid point within
the tower huh?
No debris shooting out the plane hole though!
WildCat
NWO Master Conspirator
- Joined
- Mar 23, 2003
- Messages
- 59,856
It's called gravity.