Mesh effecting the convergence
 

Could some one please suggest me how to check if the high residuals in a CFD simulation are a result of mesh quality problems.

I mean I just want to make all the possible cross checks to confirm if the mesh itself is not causing any convergence problems.

so I request suggestions to be really sure with the kind of mesh being used for the simulation.

I'm particularly refering to the mesh checks to be done in the CFD Post ( may be like creating some IsoVolumes (or) so...) (or) from the .out file but not to the basic quality checks in the mesher itself

make different mesh size according to ASME policy, and calculate your target of solution (for example torque value) per each mesh size and draw the chart of targer vs. mesh size. when the slope of that line descends, you can choose the smallest mesh henceforth.

I usually use a max. residual of 1e-3 as the convergence target. However outputed to the CFD post is only a distribution of residuals and not the max (or) RMS residuals.

So if I wanted to create IsoVolumes to residuals in CFD post is it fine to choose residuals above the 1e-3 value.

I'm only asking for a kind of analogy between a residual limit set as convergence target and the residual limit above which the residuals have to be looked on in CFD Post from IsoVolumes

The max residual is simply the maximum of the residual field and RMS is the RMS of the field. You can use the function calculator in CFD-Post to calculate ths and hopefully it will match the residuals reported in the output file.