Isentropic ist not "cause....cause...reasons...", it is in accordance with the laws of thermodynamics (and is not about accoustics).
If "sound being isentropic!" is what you got from that source and the ensuing discussion, you have convincingly proven that is you, who hasn't a clue.
Yeah...okay...
Let's repost the claptrap source and see what it defines as being isentropic at the nozzle:
""Isentropic flows occur when the change in flow variables is small and gradual, such as the ideal flow through the nozzle shown above. The generation of sound waves is an isentropic process. A supersonic flow that is turned while the flow area increases is also isentropic. We call this an isentropic expansion because of the area increase."
Now, knowing that gas released to the confines of a vacuum does 0 work, and knowing the entirety of the nozzle (both the outside of the bell and the inside of the bell) are exposed to vacuum, neither of the conditions for "isentropic process, " are met.
Rockets working in a vacuum really fits in nicely with accepted and proven physical laws.
If they were, we would see the evidence in the videos.
Instead, what we see, is the exact opposite.
Whereas I still haven't seen a plausible explanation, why/how the force propelling rockets in an atmosphere could suddenly disappear when the rocket is surrounded by a vacuum.
Because release of gas into a vacuum results in the free expansion of that gas and not a defined plume on which the rocket can act.
All relevant factors are (in essence) the same ... so where does the force (that obviously is at work in an atmosphere) disappear to?
iC
It disappears when gas is released into a vacuum.
W = F
F = m/a
Gas = m
Since we know that gas > 0, that must mean that acceleration must = 0, since F = 0 when gas is released to a vacuum.
Essentially what you guys are writing is that Joule's Law is wrong and that gas when released to a vacuum can do work.
That's just plain wrong.
And I ain't goin' for it.
Especially since the video evidence proves I am right.
Rockets cannot work in a vacuum.
Because the method by which rockets propel themselves (thrust, provided by expelling gas from the nozzle at the rear) is fine and dandy as long is there is surrounding pressure to contain a plume.
Here is an intuitive way to understand how a rocket can work in a vacuum :
The exploding gas within the rocket moves at high velocity in all directions. The gas moving in the same direction as the rocket pushes on the rocket, while the gas moving in the opposite direction (the gas being expelled) doesn't push on anything. The net result is that the exploding gas pushes the rocket forward.
The gas isn't exploding inside the rocket.
Except in the case of some launches.
Just stop with ignorance.