483 reputation
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bio website dariocortese.weebly.com
location Bristol, United Kingdom
age 25
visits member for 2 years, 5 months
seen Nov 22 at 17:14

Knowledge and understanding are quite different. Only understanding can lead to being, whereas knowledge is nothing but a passing presence in it. (G.Gurdjieff)


Jul
3
comment Does irrotational imply inviscid?
I retry to formulate my question and give a possible answer : for irrotationality I have laplacian of the velocity equal to zero, so that I can just write the Euler equation, no matter the viscosity. If the fluid is even quasi-inertia-less, I neglet the inertia term (this is an approximation that must pass through the density and characteristic lenght and velocities) , and I get $\nabla p = \boldsymbol 0$, which is the actual low-Re irrotational equation.
Jul
3
comment Does irrotational imply inviscid?
At first, thanks for the answers. Actually, this was the reason I took the 2D case (K.theorem) "However, in that case you typically want to preserve the viscous term." I can't, because the laplacian of $u$ vanishes, and I usually work with low Re flows with the incompressible condition satisfied.
Jul
3
comment Does irrotational imply inviscid?
Yes, clearly. My doubt was about the possibility to have an irrotational flow at low Reynolds numbers. This is possible only if the inertia is neglettable, and this can be only by means of lenght and density, because the viscosity doesn't enter in the eq- of motion for an irrotational flow. Is that true?
Jul
3
awarded  Autobiographer
Jul
3
awarded  Student
Jul
3
awarded  Supporter
Jul
3
suggested suggested edit on How to measure resistance of DI water
Jul
3
asked Does irrotational imply inviscid?
Jul
2
revised How to calculate time dilation in approaching speed of light
I just edited the formulae with Latex
Jul
2
suggested suggested edit on How to calculate time dilation in approaching speed of light
Jul
2
awarded  Scholar
Jul
2
accepted Why airplanes fly: the final truth
Jul
2
comment Why airplanes fly: the final truth
Thanks, I already knew these references! :)
Jul
1
awarded  Commentator
Jun
30
comment Why airplanes fly: the final truth
Get it, thanks. Could you at last give me an advice about a good book about flight for someone with a background in physics but totally in the dark about the engineering of machines, etc?
Jun
30
comment Why airplanes fly: the final truth
Great, so what about the Bernoulli effect? It is just irrelevant because of the non-conservation of energy, or is less relevant in comparison with the action-reaction push? And which is the role of the Starting Vortex?
Jun
30
comment Why airplanes fly: the final truth
So, you are saying that even a symmetric airfoil can fly, using in that case the change of angle of attack to deflect more air up or down? But if I have a symmetric airfoil the "AoA"-like, is such that the same amount of air is pushed down and up, so I couldn't receive an effective lift. Am I right?
Jun
30
comment Why airplanes fly: the final truth
I agree, but if this was true these airfoils shouldn't fly upsidedown, as they does. Because opposing the the orientation of the airfoil, we would oppose the quantity of air pushed up and pushed down. Or not?
Jun
30
revised Why airplanes fly: the final truth
deleted 2 characters in body
Jun
30
revised Why airplanes fly: the final truth
edited title