Recent content by boneh3ad

You are correct, it does not apply to adiabatic, irreversible processes. But that's kind built right into the word itself: isentropic. That implies the process must be constant-entropy, i.e., reversible. I don't immediately know why the site you link is using it without specifying the...

Just remove the question from "defense contractors" and think about it for any job in engineering. The engineering challenges at, say, Ford, are still going to be more complex than what a student typically sees in school. I don't know of any mechanical engineering programs that have required...

I just can't help but wonder how this passed peer review in an actual journal. It's a fun exercise, but contributes nothing to the field.

I mean, the definition of a blast wave requires it to be supersonic. It will eventually weaken into an acoustic wave. So that was pretty silly by said poster.

"...truth ... is much too complicated to allow anything but approximations..." - John von Neumann, 1947

This is also just a scaled technology demonstrator. Boom intends to build a 64-80 passenger airliner that may or may not incorporate sonic boom mitigation technology used by the X-59 (assuming Boom doesn't fold at some point and the X-59 is successful, of course).

Speed actually helps you here. The air gets thinner, sure, but as you move faster, you can ingest a larger volume per second, which can at least partially make up for lower density. There's still a limit, of course.

"News" articles citing no sources other than Chinese state media should be treated as what they are: propaganda. Interesting Engineering is not a serious source of journalism and has published loads of nonsense in the past.

Yeah I already told you I'm pretty sure there was a sign error somewhere. If I get the chance, I'll go back and find the error. Either way, I still don't understand the obsession of finding ##Q##.

I just looked at my solution and clearly I screwed something up because it predicts flow and a lifting of the cap when there is zero pressure in the pipe. Ha! Looking for where I likely made a typo, probably won't get to it until later.

Why are you solving for ##Q##? Wasn't the goal to find ##h## as a function of pressure in the pipe?

If you just rearrange all the three boxed equations I wrote so that you get ##h = f(D,p_g,W)##, it's a pretty compact, closed form solution that seems to make sense. I just didn't want to write it out because I didn't go back and double check everything or test it to make sure all the behavior...

The way you have the CV drawn, the elevation head will be minimal. This is especially true if the fluid medium is air. Otherwise, you are correct that an inviscid flow through a pipe with no external forces would have no pressure drop recorded. However, we have an external force here in that...

I got a bit hasty in my early reply in addition to suffering from the ##\LaTeX## bug. It happens when I try to do control volumes while on Zoom calls. Ultimately, @erobz is on the right track in #30. If you use that control volume (though I would draw the outlet to be even with the inner edge...

FYI, ##\nabla\cdot\vec{u}=0## is not a "small Navier-Stokes equation." It's the continuity equation for an incompressible fluid. It states that the divergence of the velocity field (i.e., the dilatation of the fluid element passing through that flow field) is zero. I am not really sure what you...