|November 23, 2009, 09:53||
Probable bug with laplacian steady state
Join Date: Mar 2009
Location: Polonghera, Cuneo, Italy
Posts: 27Rep Power: 10
I noticed this stange behaviour with OpenFOAM.
I've built a solver that only solve the laplacian (steady state version of laplacianFoam). I've tested this solver with the cavity geometry (icoFoam folder) where I set the boundaries value of my field in this way:
movingWall: fixedValue uniform 1
InternalField: fixedValue uniform 1
The analitic solution of this problem is that values of the field converged to the value 1, so in this case the initial solution correspond to the exact solution. The expected behaviour is that at first "time" step the solver of the linear system only does one (or zero) step and the convergence is achived. But, even if the correct solution is achived, the solvers needs many iterations and the initialResidual value doesn't decrese.
I've tried many experiment with different initial values and my oppinion is that ther is a converging problem to the uniform solution.
Someone can say me why?
...The best way to acquire new knowledge is to share it...
|November 23, 2009, 20:31||
Join Date: Mar 2009
Location: Ames, Iowa, United States
Posts: 1,910Rep Power: 28
did you try to run the case with the original laplacianFoam? It should give you a set of lines with initial and final residuals equal to zero.
The solution to that problem is always identical to the initial condition since all the fluxes are zero (on fixedWalls by default, and due to the equal value of T on movingWall and inside the system), as a consequence the initial residual should be zero also in the unsteady case.
How did you code the steady solver?
P.S. I'm Italian too
GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats.
OpenQBMM - An open-source implementation of quadrature-based moment methods.
To obtain more accurate answers, please specify the version of OpenFOAM you are using.
|Thread||Thread Starter||Forum||Replies||Last Post|
|Calculation of the Governing Equations||Mihail||CFX||7||September 7, 2014 06:27|
|mass flow in is not equal to mass flow out||saii||CFX||2||September 18, 2009 08:07|
|Mass Diffusion: Transient and Steady State BC||rval||CFX||3||November 19, 2008 01:52|
|plz help,urgent, vof model steady state||Garima Chaudhary||FLUENT||2||May 30, 2007 04:38|
|steady state, laminar vof_model||Garima Chaudhary||FLUENT||0||May 24, 2007 03:11|