Maverick's World

Missing Physics - The 9/11 Towers to Dust Theory

NIST has very wisely stayed away from describing the physics of the collapse of the WTC towers. Most ordinary observers have seen the videos of the dust clouds and wondered how a 100 story concrete building could come down like that.

In the space created by NIST's unwillingness to address the issue of the collapse and the public's fascination with the terrible events of 9/11, a number of conspiracy theorists have embedded themselves.

I don't wish to debunk anything - I believe everyone is entitled to their own views.

I do wish to point out though that in the reams of material on the internet about the tower collapse, two pieces of physics are largely missing. Both these physics pieces could account for a good fraction of the phenomenology observed.

We can accept the following did happen on 9/11. Some kind of airplane (or flying thing with lots of aviation turbine fuel) flew into a building. The fuel inside the "flying thingy" ignited inside the building and caused a massive inferno. I happen to think the "flying thingy" was an airplane [see videos from Fresh Kills]

Usually when you have an inferno like that - you get a convectional flow cell that transports the burning matter and the accompanying hot air in one direction. The exact direction this chooses is dependent heavily on the exact nature of the burn, but after a brief amount of chaotic behavior the convection cell structure stabilizes.

Once a steady-ish pattern of flow is established, a relatively simple set of energy transport processes are put in place. The first energy transport is along the direction of the flow and the second energy transport is perpendicular to the direction of the flow.  If the flow brushes against a stationary object - this cross-flow energy transfer has an inter-facial aspect to it - i.e. energy is transferred from the flow to the stationary object even if the object isn't directly in the way of the flow.

This brings me to the two missing pieces of physics.

The first piece of physics that is missing is cavitation [1].

A lot of people have talked about the absence of extremely high temperatures which could cause powder formation seen in the WTC debris. This part is correct [2].  The thing is though - you don't need high temperature to powder things, you can do it with cavitation [3]. The exact physics of cavitation is still somewhat mysterious but we know it happens in many systems. If I have a very high velocity (high Reynolds Number) flow near a concrete column, even at relatively low temperatures I will see a remarkable amount of cavitation near the surface and then we will see fractures propagating into the concrete. The erosion due to the turbulent flow proximate to the concrete could produce a significant weakening of the columns [4]. Once sufficient weakening has occurred, the concrete column which is under compression should buckle [5] spewing out tiny pieces of concrete at moving at extremely high speeds.

This brings me to the second piece of missing physics - pyroclastic flow [6].

Again traditional literature on pyroclastic flow describes it loosely as high temperature, fast moving transport of rock and air (above ground) /water(if the volcano is underwater). But if you think about it carefully, what you need for significant momentum transfer is the entrainment of sufficient amounts of rock in a fast moving flow. Once that happens - the flow is just as destructive as the traditional pyroclastic kind seen at volcanoes. Perhaps a good example of this what was seen in the famed Yosemite National Park 1996 event [7], where a slab of granite weighing several hundred tons fell to a thousand or so feet on to the forests below [8]. In that event too we saw similar destruction to a pyroclastic flow - but without the heat. [9]

As the small pieces of concrete that spew out of the buckling concrete get entrained in the flow, they will act in a fashion analogous to a traditional pyroclastic flow. This will powder anything in their path. This kind of "pyroclastic flow" would turn to dust before your very eyes. The effect would be similar to the action of a ball mill [see 5.08 in 10] or a jet mill [11].

If you add these missing pieces to what is known about the collapse, it may help you explain what you see without resorting to "Star Trek Physics" i.e. ("Free Energy", "Directed Energy") .

posted by maverick @ 8:42 AM