Wait! If this is 2D simulation, then this cannot be vortecies. Vortecies only happen in 3D flow. Check the pressure contour if it is low pressure at the center it is a vortex. However, in this case it will be recirculation bubbles (if the simulation is fully 2D not quasi).
It generally appears at a Reynolds number between 80 and 1.0E+5. Depending on how long is the cylinder and how viscous is your fluid, the velocity regime you'll need to set will be different in each case. Lower than 80 the structures that appear are stable and higher than 1.0E+5 the regime is chaotic.
@@YourPhysicsSimulator This may be a duuuuuuumb question, but does the hemisphere which this occurs as in Earth North or South have any affect on which side, left or right, the oscillation begins? The drag appears stable then something upset the stability. I expect a force greater than the viscosity’s adhesive effects , then the burble lets go. Also as fluids and gases have mass, is gravity a factor? Photons have dual personalities, mass or energy well it depends, correct? Refraction occurs as light passes near an object and in photography, we were taught, ( B.S. Photography, retired ) a lens will suffer a loss of resolution when the aperture is too small. The light refraction will cause this to happen. The light begins to act as waves as you have witnesses with dual pin hole experiments in classic physics. I do wonder what is happening on the molecular level or even on the quantum level. How deep does the rabbit hole go?
@@crawford323 For the first question in these models gravity is not considered. The place towards where te oscillation begins is determined purely by the Reynolds number; this means the viscosity, geometry and inflow velocity. In nonlinear dynamics this can be named bifurcation, from stable to periodic and then chaos (this Von Kármán phenomenon is kinda different but has some analogies to these nonlinear dynamics description since after all Navier-Stokes equations are nonlinear haha). In a general and therefore real case gravity is a real thing but what you mean with North and South pole is due to a force called Coriolis that is due to Earth's rotation. It's not a real force, tho, it's an effect of Earth's motion. And about Von Kármán I've never seen anyone say that Coriolis has an effect on it... But since this has to do with the flow separation I don't think so, but maybe it does have some effect, but probably not relevant. And your second question everything can go as deep as you want, but the fastest thing to answer to you is that optics is a more specific area of electromagnetism and the light you see is described by measurable electric and magnetic fields that oscillate is perpendicular directions. But if you go deeper you find quantum descriptions of electromagnetic fields (Quantum Field Theory). But in esence, the optical process is what you said... but every simple process can have very deep and intrincate consequences. If you want a good explanation of refraction and the double slit experiments watch this czcams.com/video/p-MNSLsjjdo/video.html
@@crawford323 A good question considering what happens when water flows down the plughole. The answer is no as far as I know. The breaking of stability is spontaneous and not affected by which hemisphere we are in.
In principle, yes. We could use a random number generator to add a little bit of Brownian motion to induce an instability and make sure successive runs of the simulation have different outcomes. Viscosity is like Brownian motion anyway.
They make such a beautiful simulation and then upload it at 240p. This is a crime against humanity
It's interesting to see how it starts off symmetric and then goes very much asymmetric.
Dont know why this was recommended to me, but quite interesting to watch
idk how i got here but this looks cool, i guess???
At Re 1000, transition to 3D is inevitable.
🙂🍀🍀🍀
Wait! If this is 2D simulation, then this cannot be vortecies. Vortecies only happen in 3D flow. Check the pressure contour if it is low pressure at the center it is a vortex. However, in this case it will be recirculation bubbles (if the simulation is fully 2D not quasi).
L am in the 2021 🤣 anf k am here
At what velocity does this appear and does this hold true at different velocities and densities? Can you imagine if Sighard Horner had such tools?
It generally appears at a Reynolds number between 80 and 1.0E+5. Depending on how long is the cylinder and how viscous is your fluid, the velocity regime you'll need to set will be different in each case. Lower than 80 the structures that appear are stable and higher than 1.0E+5 the regime is chaotic.
@@YourPhysicsSimulator This may be a duuuuuuumb question, but does the hemisphere which this occurs as in Earth North or South have any affect on which side, left or right, the oscillation begins? The drag appears stable then something upset the stability. I expect a force greater than the viscosity’s adhesive effects , then the burble lets go. Also as fluids and gases have mass, is gravity a factor?
Photons have dual personalities, mass or energy well it depends, correct? Refraction occurs as light passes near an object and in photography, we were taught, ( B.S. Photography, retired ) a lens will suffer a loss of resolution when the aperture is too small. The light refraction will cause this to happen. The light begins to act as waves as you have witnesses with dual pin hole experiments in classic physics.
I do wonder what is happening on the molecular level or even on the quantum level. How deep does the rabbit hole go?
@@crawford323 For the first question in these models gravity is not considered. The place towards where te oscillation begins is determined purely by the Reynolds number; this means the viscosity, geometry and inflow velocity. In nonlinear dynamics this can be named bifurcation, from stable to periodic and then chaos (this Von Kármán phenomenon is kinda different but has some analogies to these nonlinear dynamics description since after all Navier-Stokes equations are nonlinear haha).
In a general and therefore real case gravity is a real thing but what you mean with North and South pole is due to a force called Coriolis that is due to Earth's rotation. It's not a real force, tho, it's an effect of Earth's motion. And about Von Kármán I've never seen anyone say that Coriolis has an effect on it... But since this has to do with the flow separation I don't think so, but maybe it does have some effect, but probably not relevant.
And your second question everything can go as deep as you want, but the fastest thing to answer to you is that optics is a more specific area of electromagnetism and the light you see is described by measurable electric and magnetic fields that oscillate is perpendicular directions. But if you go deeper you find quantum descriptions of electromagnetic fields (Quantum Field Theory). But in esence, the optical process is what you said... but every simple process can have very deep and intrincate consequences. If you want a good explanation of refraction and the double slit experiments watch this czcams.com/video/p-MNSLsjjdo/video.html
@@crawford323 A good question considering what happens when water flows down the plughole. The answer is no as far as I know. The breaking of stability is spontaneous and not affected by which hemisphere we are in.
In a perfect mathematical world, would the system not stay even?
In principle, yes. We could use a random number generator to add a little bit of Brownian motion to induce an instability and make sure successive runs of the simulation have different outcomes. Viscosity is like Brownian motion anyway.
Why was this recommended to me 12 years after the video was published?
I dont even know what this is