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 Author Comment/Response George 07/25/12 6:38pm Hello Folks, I am new to Mathematica, but it seems to be the most suitable tool for my issue. I have to solve a equation which is similar to heat equation on a sphere surface. The exact expression in a spherical coordinates system is (in LaTeX) : \frac{\partial{h}}{\partial t} = \frac{1}{n} \left[ \frac{1}{r^2 \sin^2{\phi}} \frac{\partial}{\partial \theta} \left( K \frac{\partial h}{\partial \theta} \right) + \frac{1}{r^2 \sin \phi} \frac{\partial}{\partial \phi} \left( K \sin \phi \frac{\partial h}{\partial \phi}\right) + s(\theta,\phi,t) \right] K is kind of a diffusion coeff. s a source term (varying in time and space) and n a constant (although it might depends on \phi and \theta). \theta and \phi are defined here in a mathematical way. r the radius (constant as we deal with a perfect sphere). (no variation regarding the radius, we only look at the surface of the sphere). I found that in Mathematica, and in a Cartesian frame, such equation (somewhat not exactly the same but similar) would be: R = 1 K = 34 myfunc = NDSolve[{D[h[x, y, t], t] == R*(D[h[x, y, t], x, x] + D[h[x, y, t], y, y]), h[x, y, 0] == 0, h[0, y, t] == K*t, h[9, y, t] == K*t, h[x, 0, t] == K*t, h[x, 9, t] == K*t}, h, {x, 0, 9}, {y, 0, 9}, {t, 0, 6}]; I'm kind of stuck right now, because I do not know how can I switch to the spherical frame. I would appreciate any ideas/suggestions. Thanks a lot and sorry for bothering you guys with this. G. URL: ,

 Subject (listing for 'Heat equation at sphere's surface') Author Date Posted Heat equation at sphere's surface George 07/25/12 6:38pm Re: Heat equation at sphere's surface Michael 07/26/12 07:56am Re: Re: Heat equation at sphere's surface George 07/26/12 9:14pm Re: Heat equation at sphere's surface George 07/28/12 7:13pm
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