Learn about the proof of Lamb-Chaplygin dipole

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SUMMARY

The discussion focuses on the proof of the Lamb-Chaplygin dipole, specifically the mathematical derivation involving the stream function. Key steps include replacing velocity components with the stream function, deriving the horizontal momentum equations, and eliminating pressure terms to form a single equation in ψ. The proof leads to a differential equation in polar coordinates, which is satisfied by Bessel's functions. The primary resources referenced for this proof are two links, with the first link suggested to contain the proof on pages 166-174.

PREREQUISITES
  • Understanding of fluid dynamics concepts, particularly the stream function.
  • Familiarity with differential equations and their applications in physics.
  • Knowledge of Bessel functions and their properties.
  • Basic proficiency in polar coordinate transformations.
NEXT STEPS
  • Study the derivation of the stream function in fluid dynamics.
  • Research the properties and applications of Bessel functions in solving differential equations.
  • Learn about the implications of the Lamb-Chaplygin dipole in fluid mechanics.
  • Explore the mathematical techniques for transforming equations into polar coordinates.
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Students and researchers in fluid dynamics, mathematicians focusing on differential equations, and anyone interested in advanced topics related to the Lamb-Chaplygin dipole solution.

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I learn about Lamb-Chaplygin dipole and try to find the proof of this topic.
so I found the next link (is named: link1): https://docs.google.com/file/d/0B3-t1lLIJWOLc2NmT1RIWV9HOWs/edit?usp=sharing&pli=1

In addition, I found another link (is named: link2): http://ics.org.ru/doc?pdf=875&dir=e

can anyone tell me please on which pages (and of which link) the proof is found?
I think the proof is found only at link1: 166-174 but I'm not sure.

any help appreciated!
 
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explanation the next steps in other words (dipole)

I am trying to understand the lamb-chaplygin dipole solution.
can someone explain me the green lines in other words please?

this is the proof:

When introducing the stream function, the steps that you usually take are as follows:
1) replace u and v by the stream function.
2) Derive the horizontal momentum equation (for u) with respect to y and the other with respect to x.
3) Eliminate the pressure term, to end up with a single equation in ψ.

so:

v = -∂ψ/∂x, u = ∂ψ/∂y

(∂^2)ψ/∂x^2 + (∂^2)ψ/∂y^2 = f(ψ)

if we put f(ψ) = -(k^2)*ψ. where k is a constant, and transform to polar coordinates r, θ, we get:

(d^2)ψ/ dr^2 + (1/r) * (dψ/dr) + (1/r^2) * (d^2)ψ/ dθ^2 + (k^2)*ψ = 0

which is satisfied by:
29y8fo.jpg


where Js is a bassel's function.


any help appreciated! thanks!
 

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