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-   -   solution singularity (http://www.cfd-online.com/Forums/openfoam/68478-solution-singularity.html)

mugsy September 21, 2009 18:50

solution singularity
 
1 Attachment(s)
Hello, I am a high school Physics teacher and am teaching an aerospace topic. I get my students to build airfoils and test them but I also wnat to set up some simple scenarios in OpenFOAM for them to run. I used the sonicTurbFoam tutorial prism and redesigned the mesh into a simple airfoil and hey presto it worked beautifully. Next I put in a saw toothed airfoil that has no chance of flying (all the other parts are the same, only the messh changed). Unfortunately I get solution singularities and get nowhere. I have adjusted the timestep, checked all boundary conditions and judging from the forum the problem is with relaxing the equations which I have no idea about. I tried typing solutionrelaxation { U 0.7; } into fvsolution but this had no affect. Can anyone help me with this??? I have attached the file if anyone is kind enough to help me out. Many thanks Scott

mugsy September 24, 2009 11:19

fixed the problem
 
Well after 4 days of constant fiddling around the problem is solved. It would have helped immensely if someone out there had helped me!!!! Oh well. This is for anyone else struggling with singularities. First I ran refineMesh to smooth out my mesh then I increased the tolerances of the solvers in fvSolutions eg solvers { p PBiCG { preconditioner DILU; tolerance 1e-08; (increase lots) relTol 0; }; rho PCG { preconditioner DIC; tolerance 1e-05; (increase lots) relTol Hope this helps someone out there. Scott


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