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Timeline for Linearized stream function

Current License: CC BY-SA 3.0

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Feb 3, 2016 at 18:19 history bounty ended charlestoncrabb
Feb 3, 2016 at 14:15 comment added Willie Wong some arbitrary function $f$ [e.g. the case of traveling solitons]. But if you expect wave like behaviour than it is natural to postulate that $f$ takes the form of $\exp i \alpha$ and see what happens.)
Feb 3, 2016 at 14:13 comment added Willie Wong @charlestoncrabb: "why it works" is basically answered by "you plug it in and see what happens". The motivation behind the choice is that parallel shear flow can be imagined to be a flow between two plates, where the fluid is flowing in the $x$ direction with velocity depending on the $y$ direction only. If you add a perturbation, you sort of intuitively expect the perturbation to be carried down stream in a traveling wave. So a first order approximation is precisely of the form $\Psi(y) \exp (i \alpha (x - ct))$. (A traveling wave solution more generally should depend on $f(x-ct)$ for
Feb 3, 2016 at 0:38 comment added charlestoncrabb Thank you very much for your thoughtful response. What you've said makes sense. I awarded the bounty, though I am still curious what the motivation behind choosing $\phi=\Psi(y)e^{ia(x-ct)}$. Is there a nice intuitive connection between this ansatz and why it works?
Feb 3, 2016 at 0:36 vote accept charlestoncrabb
Feb 1, 2016 at 15:36 history answered Willie Wong CC BY-SA 3.0