Fluid dynamics

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  1. Calira's Avatar
    • Adored and Respected Member
    • Location: England
    • Posts: 548
    Fluid dynamics
    I'm not sure the best way to start this problem:

    I have a model of a 2D flow given by the potential
    w(z) = \frac{-1}{2\pi}ln(z+\frac{a^2}{z})
    and need to find the velocity components in the x and y directions.

    I know that \frac{dw}{dz} = u - iv but when I differentiate w and then try and split into real and imaginary components, I get horribly long fractions which doesn't seem right.
    I've also tried writing w = \Phi + i\Psi and then evaluating the partial derivatives of phi and psi to get the velocity components, but again that leads to some very messy algebra.

    Am I missing a slick method, or do I have to try and force my way through the algebra?
    Any pointers in the right direction are welcome.
  2. Coursework.info's Avatar
    • Retired TSR Help Bot
    • Location: That galaxy over there
    Fluid dynamics
    It's been a while since you posted and nobody's replied yet...maybe you should check out MarkedbyTeachers.com, TSR's sister site. It has the largest library of coursework and essays in the UK.

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  3. yusufu's Avatar
    • TSR Idol
    • Posts: 7,509
    Re: Fluid dynamics
    IIRC you want u=\nabla \phi for \phi a standard non-complex potential. I can't recall how it works for a complex potential.
    Are you simply trying to find \frac{dw}{dz} and then taking the real and imaginary parts as components for u?
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