On Sat, Feb 27, 2016 at 4:47 PM, Jayaraman, Vegnesh <vjayr...@illinois.edu> wrote:
> Hi > > > I am trying to change the Poisson Tutorial given on the libmesh webpage to > solve in an axis-symmetric domain. However, I am not getting the result I > expected. I have detailed the changes I made in the code. Please let me > know the place I am going wrong if possible or the correct way to solve an > axissymetric problem using libmesh. > > I am trying to solve an axissymmetric coordinates R-Z with x variable in > libmesh corresponding to Z and y variable corresponding to R. This is a little unusual, it would be more standard to make the x coordinate correspond to R and the y coordinate correspond to Z. > I modified the example three given in the tutorial page. > http://libmesh.github.io/examples/introduction_ex3.html > > I saw in a previous libmesh user thread, which told we need to multiple > each integration by the 'r' coordinate to solve the problem. Correct, which for you is apparently q_point[qp](1), not (0). > I tried that but that does not seem to work. Please be more specific about what does not work. Did you get the wrong answer? Did the code crash? > While doing this I ensured that the numerically calculated RHS function > corresponds to the laplacian in cylindrical polar coordinates. > This is definitely a possible source of error. I'd recommend computing the Laplacian of your exact solution analytically (in polar coords) and using that for RHS assembly. The finite-differencing approach used to set the RHS in the example is not essential to the finite element method. -- John ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
