[Nek5000-users] symmetry boundary conditions and genmap

[nek5000-users at lists.mcs.anl.gov]

Paul,

I fixed my python script and was able to generate the map file. I noticed, however, in the output the following message:
not connected           1           3           9           0
Could you please explain what means this message?

Thanks,
Marco
> On Jul 1, 2016, at 3:03 PM, nek5000-users at lists.mcs.anl.gov wrote:
> 
> 
> Hi Marco,
> 
> It looks maybe like you replaced "W" by "SYM"  ?
> 
> In the .rea file, if a line has a character that is read by nek, then the line has to be formatted,
> which means that spaces in the line are important.
> 
> Thus, you should replace "W  "  ('W-space-space) by "SYM"  , i.e., all bcs are read as 3 character
> strings.
> 
> Now, concerning SYM, there is another constraint --- namely the following:
> 
> Any SYM boundary must be aligned with either X , Y, or Z unit normals, unless you're using the
> stress formulation.
> 
> The reason is that, say, for a SYM boundary that has unit normal in the Z direction, the velocity
> bcs are:
> 
>   du/dz = 0 ,  dv/dz = 0,  w=0
> 
> That is, Dirichlet for w and Neumann for u and v.
> 
> If the SYM bc is not aligned, it ends up being a mixed bc for the 3 velocity components, which
> in Nek can at present be handled only with the stress formulation, which means PN-PN-2, and 
> not PN-PN.
> 
> Best, Paul
> 
> ________________________________________
> From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
> Sent: Thursday, June 30, 2016 7:46 AM
> To: nek5000-users at lists.mcs.anl.gov
> Subject: [Nek5000-users] symmetry boundary conditions and genmap
> 
> Hello,
> 
> I have two rea files that are exactly identical but for the boundary conditions: one has ‘W’ and the other one has ‘SYM’. If I am not mistaken, the ‘SYM’ boundary type is supported by Nek5000 but is causing problem when I try to generate a map file with genmap. It returns the following error message:
> reading .rea file data ...
>  ERROR: error reading    1       79200      299357
>  aborting 530 in routine rdbdry.
> 
>           1  quit
> 
> The rea file with ‘W’ boundary type successfully goes through the genmap script. Is there anything I should be aware when setting SYM bc type in the rea file?
> 
> I could not find any related post in the archive of the mailing list.
> 
> Thanks,
> Marco
> 
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>