inlet/outlet + moving walls + periodicity

Hi everyone,

I've modified the example 07_CurrentHull to include moving walls + periodicity in the computations. The fluid flow is set to 1.71unit/s-1 in the X direction.

  • Walls are defined as following :

<setmkbound mk="0" />


                       <boxfill>bottom | front | back</boxfill>

                       <point x="-2" y="-1.0" z="0" />

                       <size x="5" y="2" z="0.4" />


  • Movement is defined as following :


           <objreal ref="0">

               <begin mov="1" start="0" finish="100" />

               <mvrect id="1" duration="100">

                   <velini x="1.71" y="0" z="0" units_comment="m/s" />

                   <vel x="1.71" y="0" z="0" units_comment="m/s" />




  • Periodicity is defined as following :

<parameter key="XPeriodicIncZ" value="0" comment="Increase of Z with periodic BC in axis X" units_comment="metres (m)" />

Boundaries and surface are exported in VTK. Outputs are displayed in blender. Here is the initial set (Hull_0000, Box_0000, Surface_0000) :

Here are the the steps (Hull_0001, Box_0001, Surface_0001) and (Hull_0010, Box_0010, Surface_0010) :

Although the Xperiodicity seems to be correct, the orientation of the box do not match its initial presets. What am I doing wrong ?

Thanks in advance for your kind help. Cheers,


  • Hi everyone,

    doing some test to understand where the issue could be, I find that :

    • the vtk output issue do not appears at frame 0,1,2,3, but starts at frame 4
    • the vtk output issue happens when importing in Blender 2.9 + visualsphysic add on and in Paraview 5.0
    • wall to fluid interaction is the same using moving wall or fixed wall

    It does not seem possible to perform 3d calculations with inlet/outlet and walls moving with the flow, isn't it ?

    Any clues ? Cheers,

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