Recent content by MarkoA

  1. M

    I General question about correct notation

    Hi, I have a question about how to write down the following problem in a thesis. I have a standing sinusodial wave with amplitude: |\hat{q}_n| which I want to express as superposition of two traveling waves. Would you suggest do write the sum in the last line like I did, or has somebody a...
  2. M

    I Normal vector on complex function

    Actually the real part of N looks good (plotting it in Matlab). However, I'm not sure about my imaginary part. It's more like a trial and error approach... To the background: I want to compute the the aerodynamic work on a traveling wave. I have a complex pressure p and surface displacement z...
  3. M

    I Normal vector on complex function

    Hi, I'm not sure about the the normal vector N on a complex function z(x,t) = A e^{i(\omega t + \alpha x)} My approach is that (\overline{z} beeing the conjugate of z): \Re{(\mathbf{N})} = \frac{1}{\sqrt{\frac{1}{4}(\partial x + \overline{\partial x} )^2 + \frac{1}{4}(\partial z +...
  4. M

    I Can't find a solution to this integral

    Thanks!
  5. M

    I Can't find a solution to this integral

    Thanks for your post. I start with dx. I can write e^{2i(\omega t + \alpha x)} = \cos{(2\omega t + 2\alpha x)} + i \sin{(2\omega t + 2\alpha x)} and then for the first term \cos{(2\omega t + 2\alpha x)} = \cos{(2\omega t)}\cos{(2\alpha x)} - \sin{(2\omega t)}\sin{(2\alpha x)} Thus, the first...
  6. M

    I Can't find a solution to this integral

    Hi, I try to solve this integral, but I failed... I have tried Euler's formula but it only got more and more complex. Can anyone help me? \int_{0}^{T}\int_{0}^{L}\frac{e^{2i(\omega t+\alpha x)}}{\sqrt{1-a e^{2i(\omega t+\alpha x)}}}dx dt
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    Finding the General Solution of a Wave Equation with Fourier Transformations

    Due to your help I finally managed to follow this publication. Thanks!
  8. M

    Finding the General Solution of a Wave Equation with Fourier Transformations

    Hi, following the attached paper I try to find the general solution of the following wave equation: \frac{1}{a^2} \frac{\partial^2 \phi}{\partial t^2} + \frac{2M}{a}\frac{\partial^2 \phi}{\partial x \partial t} + \overline{\beta}^2 \frac{\partial^2 \phi}{\partial x^2} =...
  9. M

    Solution of unsteady linearized potential flow PDE

    I made some progress to get equation (14) and (15). Not sure if I can already corellate the fourer constant alpha with the wave number. The equation of motion: \begin{equation} \frac{1}{a^2}\frac{\partial^2\phi}{\partial t^2} + \frac{2M}{a} \frac{\partial^2 \phi}{\partial x \partial t} +...
  10. M

    Solution of unsteady linearized potential flow PDE

    Oh... the substitution was absolutely wrong. I need to find the correlation between the potential and z..
  11. M

    Solution of unsteady linearized potential flow PDE

    I don't know. This doesn't help. What could he have done? I've heard that Duhamel's principle could be an approach of solving non-homogenious PDEs like the wave equation. Could the solution have something to do with this approach? Substituting (13) in (2) gives: \begin{equation}...
  12. M

    Solution of unsteady linearized potential flow PDE

    Hi, I have a problem following the solution of a linearized potential flow equation in a publication by Fung. The problem describes potential flow over an oscillating plate. A boundary layer is approximated by defining a subsonic layer over the panel and supersonic flow above the subsonic...
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