code_saturne User's Forum

Posted: **Wed Feb 24, 2010 8:53 pm**

I have a very newbish problem: Everytime I try to launch a test calculation Im struck with the following error message:

WARNING: BOUNDARY CONDITIONS ERROR
@    *******
@
@    In the zone out has a face already marked
@    with a zone number.
@
@    new zone number:             2
@    previous zone number:        1
@
@    It seems that zones definitions are overlapping.
@
@    The calculation will stop.

The zones I've given in Definition of BCs are simply 1,2,3 for surface groups in, out, and wall - I've tried changing the zones to numbers 4,5 and 6 with the same error appearing.

The mesh is a very simple one created in Salomé for testing; I've attached it here.

Heres the BC section from the XML

Code: Select all

<boundary_conditions>
         <boundary label="in" name="1" nature="inlet">all[]</boundary>
         <boundary label="out" name="2" nature="outlet">all[]</boundary>
         <boundary label="wall" name="3" nature="wall">all[]</boundary>
         <variable/>
         <scalar/>
         <outlet label="out"/>
         <wall label="wall"> 
            <velocity_pressure choice="off"/>
         </wall>
         <inlet label="in">
             <velocity_pressure choice="norm" direction="normal">
                 <norm>1</norm>
             </velocity_pressure>
             <turbulence choice="hydraulic_diameter">
                 <hydraulic_diameter>1</hydraulic_diameter>
             </turbulence>
         </inlet>
     </boundary_conditions>

Posted: **Wed Feb 24, 2010 9:24 pm**

Hmm it seems to work when I change >all[]< to the label of the BC manually - am I doing something wrong in the GUI?

Code: Select all

        <boundary label="in" name="1" nature="inlet">in</boundary>
        <boundary label="out" name="2" nature="outlet">out</boundary>
        <boundary label="wall" name="3" nature="wall">wall</boundary>

Version is 2.0.0RC1

Regards

/C

Posted: **Thu Feb 25, 2010 1:21 am**

Hi Claus,

Actually the zone number is (at the moment) only used when defining what we call specific physics (say e.g. combustion, electric arcs, Lagrangian modelling, ...), even if the graphical interface always defines one. The only thing required is that the zone numbers are all different.

Your problem lies in the fact that you have inverted the zone label and the zone criteria. The zone label is just an easier reminder for you: instead of having for example "range[2,4] and Y < 0.05", you can label did "my_bottom_walls" throughout the setup. In your case, the different groups of the mesh (in, out, wall) should be used as criteria and not as label.

David

Posted: **Thu Feb 25, 2010 12:22 pm**

Okay, silly me, I thought 'label' was referring to the group names. It works with entering group names in to the 'criteria' field. Thank you.

Posted: **Thu Feb 25, 2010 3:23 pm**

I think we should be more verbose in the documentation (user guide) about how to setup the calculation with the graphical interface, and also about the meaning of label, zone, criteria, ... Work to be done here ;)

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