Convergence problem when refine the mesh...

TB

Hi,

I get a steady state solution for a diffusing bend when the mesh is coarse. However, I start getting some unsteady solution when I refine the near wall mesh (O grid type is used). The pressures & velocities that I monitor at some locations inside the domain show small fluctuations along the mean values (say +/-0.2Pa at mean value of 125Pa)and the max momentum residuals stay at the order of 10^-2 (around the same magnitude for both 3) P-max residual stays at the order of 10^-4. RSM, SST, kw, SSG, RNG ke models all show similar phenomenon (except for standard ke).

What should I do about this situation? Should I stick with coarse mesh solution? Can I use this unconverged solution? I will need the steady state solution to run the transient simulation later.

Thanks for any help here.