<div dir="ltr"><div><div>Hi Johan,<br><br></div>Here is a piece of code adapted from one of my simulations that you could try to include in you userchk.<br><br><span style="font-family:monospace,monospace">      include 'TSTEP' ! time, ifield<br>      include 'INPUT' ! cbc <br><br></span></div><div><span style="font-family:monospace,monospace">      integer iel, ifc<br></span></div><div><span style="font-family:monospace,monospace">      integer icalld<br></span></div><div><span style="font-family:monospace,monospace">      save icalld<br></span></div><div><span style="font-family:monospace,monospace">      data icalld /0/<br></span></div><div><span style="font-family:monospace,monospace"><br></span></div><div><span style="font-family:monospace,monospace">      if (icalld .eq. 0 .and. ifield .eq. 1 .and. time .gt. T) then<br></span></div><div><span style="font-family:monospace,monospace">         icalld = 1<br></span></div><div><span style="font-family:monospace,monospace"> 
        nface = 2*ndim                                                  
                                                                        
                                           <br>         do iel=1,nelv    
                                                                        
                                                                        
                  <br>            do ifc=1,nface      <br>               if ("face belongs to part B") then   ! Identify boundary B here<br>                  cbc (ifc,iel,ifield) = 'O  ' ! or 'o  ' or 'on ' or 'ON ' depending on what is needed<br> 
              endif                                                      
                                                                        
                                          <br>            enddo          
                                                                        
                                                                        
                 <br>         enddo<br>         <br></span></div><div><span style="font-family:monospace,monospace">         ! Reset BC flags and masks<br></span></div><div><span style="font-family:monospace,monospace">         call setlog<br></span></div><div><span style="font-family:monospace,monospace">         call bcmask   <br></span></div><div><span style="font-family:monospace,monospace">      endif<br><br></span></div><div><span style="font-family:monospace,monospace"><font face="arial,helvetica,sans-serif">Best,</font><br></span></div><span style="font-family:monospace,monospace"><font face="arial,helvetica,sans-serif">Nicolas<br><br>P.S.: please ignore previous message, that was a wrong manipulation. </font><br></span></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Apr 11, 2018 at 2:08 PM,  <span dir="ltr"><<a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">




<div dir="ltr">
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<p>Hi Neks,</p>
<p><br>
</p>
<p>I wonder if it is possible to have boundary conditions that chage type with time?</p>
<p><br>
</p>
<p>I want to simulate a flow where I make a 'puff' of fluid through a hole in a wall.</p>
<p>After the puff is made it continues to evolve without beeing forced.</p>
<p><br>
</p>
<p>Mathematically, this is what I want:</p>
<ol style="margin-bottom:0px;margin-top:0px">
<li>Dirichlet boundary conditions (ux,uy,uz) = (0,0,1) for the velocity at a part B of the boundary up to a time T.</li><li><span>Open boundary condition for the velocity at B for time > T.</span></li></ol>
<p><br>
</p>
<p>Is this possible to implement?</p>
<p><br>
</p>
<p>Best,</p>
<p><br>
</p>
<p>Johan<br>
</p>
<p><br>
</p>
</div>
</div>

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<br></blockquote></div><br></div>