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answered total vorticity generation in 3D
Sep
1
comment What is the recommended symbol for Volumetric flow rate?
Just to be helpful -- might I suggest simply picking one, making sure you define it in the text and moving on? Surely there are bigger things to work on in the paper than this! (And it helps that either one would make sense, but either needs defined)
Aug
29
comment Tensors, indices and matrix notation - is there a common convention?
I thought that indices on top vs indices on bottom had something to do with co- or contravariance, but for what I do (fluid and solid mechanics), we only ever dealt with indices on the bottom so I don't know for sure.
Aug
29
comment Clarification of the physics involved of an orbiting body in a circular orbit
Velocity-Verlet is great, but you may want to explain (and/or provide links to) each method. At the very least, point out why Euler won't work and symplectic methods like VV are needed.
Aug
27
comment Why does the sun make me feel warm?
@CJDennis There is a question on why glass absorbs IR. I am pretty sure there are more/better ones on the site. I recall a question (I think we closed it) where somebody wanted to know how to evade detection by IR security cameras -- my suggestion was to walk around with a big, glass shield between you and the camera.
Aug
21
comment Why is the activation energy of combustion so large compared with regular bonding?
It is complicated, but the only thing I can say is consider what state minimizes the free energy of the system. All kinds of exotic things are "possible" but nature will prefer the one that is most stable. I don't know about Winner's rule so I cannot answer directly.
Aug
21
comment Why is the activation energy of combustion so large compared with regular bonding?
What are the Gibbs free energies of the system? What pathway is more stable or more favorable?
Aug
13
comment Adding fluctuations to a hydrodynamic simulation to trigger instabilities
Have you tried just adding white noise fluctuations to the temperature at the inflow? That's usually the first step in any of these types of problems. And if that doesn't work/gives wrong answers, you start looking at adding turbulence-like structures that are correlated in time and space.
Aug
12
answered Good book for learning fluid statistics
Aug
12
accepted Cellular structure in solid phase detonations
Aug
5
comment Why does it rain more at night than during the day?
possible duplicate of Do weather conditions change after sunset?
Jul
30
comment How does a converging-diverging nozzle not violate conservation of energy?
It still doesn't explain why it speeds up in supersonic flow. We know in subsonic flow, it reaches its narrowest point and then as it expands it slows down. Using your car analogy, people floor it through the narrow point and then as the road opens up again, they slow down. But supersonic this isn't the case -- pressure is always decreasing, but why does it always decrease? Why does it only do this for supersonic flow and not subsonic? I'm not trying to give you a hard time, just trying to improve the answer :)
Jul
30
comment How does a converging-diverging nozzle not violate conservation of energy?
This answer doesn't say anything wrong, but I think it's missing the key question -- why does flow accelerate with increasing area while supersonic and how is that not a violation of conservation of energy.
Jul
28
comment What causes this IR emission in UV 365nm LED?
As @dmckee pointed out, green lasers are not as simple as red. Check out this question: physics.stackexchange.com/questions/173677/… It is likely something similar here.
Jul
24
comment Could a Jumbo Jet aircraft fly on paper wings?
And also -- are you referring to a paper skin, ie. the wing surface itself, or the entire wing structure (skin, ribs, spars, etc)?
Jul
24
comment Could a Jumbo Jet aircraft fly on paper wings?
How thick of a paper wing are you talking about? The wings still have to hold the weight of the aircraft while in the air so a single sheet of paper would never work. But paper stacked 4 feet thick like a regular wing? Maybe. The wing spar does a lot more than hold the weight of the things attached to the wing.
Jul
24
comment 9-point stencil “equivalent” for advection equation
I hope you already had all of those equations typed up somewhere and could just copy them over. Otherwise, that's way too much work MathJax'ing an answer!
Jul
23
comment If you compress air to a large enough pressure do new molecules form that have a large activation energy?
What do you mean molecules with a large activation energy? Chemical reactions have an activation energy, but I'm not familiar with that phrase in regards to molecules. Do you mean a large energy requirement to break the new molecules apart again, like pressing carbon into diamonds?
Jul
19
comment No diffusion term in conservation of mass in Navier-Stokes equations?
@csss You can definitely do that. But in a pure fluid, there is no differences in mass. Water molecules all weigh the same, so there's no "layers" of different masses. I left an answer explaining that reasoning.
Jul
19
comment No diffusion term in conservation of mass in Navier-Stokes equations?
@KyleKanos You can do it mathematically, I just left and answer doing it descriptively.