Differential equation and fluids

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SUMMARY

The discussion centers on solving a differential equation related to fluid dynamics, specifically in the context of a viscous flow problem presented in question 10.20 of a referenced textbook. The operator E has been identified, but the challenge lies in demonstrating that the function f(r) satisfies the differential equation. The proposed solution for the stream function is given as Ψ(r,θ) = f(r)·sin²(θ), which leads to the required ordinary differential equation upon substitution into the equation.

PREREQUISITES
  • Understanding of differential equations, particularly in fluid dynamics.
  • Familiarity with the concept of stream functions in fluid mechanics.
  • Knowledge of the mathematical operator notation and its application in solving equations.
  • Basic algebraic manipulation skills to handle lengthy calculations.
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  • Review the derivation of differential operators in fluid dynamics.
  • Study the application of stream functions in viscous flow problems.
  • Learn how to apply boundary conditions to differential equations in fluid mechanics.
  • Explore the use of numerical methods for solving complex differential equations.
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Students and professionals in mathematics, physics, and engineering, particularly those focusing on fluid dynamics and differential equations.

Niles
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Homework Statement


Hi guys

Please take a look at the second question in 10.20 (the question with the diff. equation):

http://books.google.com/books?id=Mq...ts=JOvnmWE-Jo&sig=FP2sASpndHBj_ETidnKSzSxsFd4

I have found the expression for the operator E, but how do I show that f(r) satiesfies the diff. equation?

The Attempt at a Solution



First thing would be to insert "psi"(r,theta) in E - but where to go from here? I am very lost.

Thanks in advance,

sincerely Niles.
 
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Niles, It would be nice if you showed the work done for obtaining the differential operator E. It is not explicitly given in your link and I have no clue whether my result is correct or not. At a certain point in time I was pressed with my nose against the screen trying to read the link because the thing does not zoom in properly. It's a fairly bad reading link. It would help to post the question in it's entire form and also to show some of your work. Principally it is just applying the operator twice to the stream function and the equation you get then has the proposed solution \Psi(r,\theta)=f(r)\cdot sin^2(\theta). The only thing to do is to put it in the equation and you will arrive at the required ordinary differential equation. As stated, I can't check anything over here because I don't have the book and it seems it is a rather lengthy algebraic journey, which I will undertake to help you, but I need to make sure that my operator is correct.
 

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