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<p style="margin-top:0;margin-bottom:0">Yes - ...</p>
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<p style="margin-top:0;margin-bottom:0">If you simply define the region(s) of interest with 'v ' for your BC,</p>
<p style="margin-top:0;margin-bottom:0">then you can simply user userbc. For example</p>
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<p style="margin-top:0;margin-bottom:0"> omega = 3</p>
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<p style="margin-top:0;margin-bottom:0"> ux=0</p>
<p style="margin-top:0;margin-bottom:0"> uy=sin(omega*time)</p>
<p style="margin-top:0;margin-bottom:0"> uz=0</p>
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<p style="margin-top:0;margin-bottom:0">would be one such function.</p>
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<p style="margin-top:0;margin-bottom:0">Paul</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Nek5000-users <nek5000-users-bounces@lists.mcs.anl.gov> on behalf of nek5000-users@lists.mcs.anl.gov <nek5000-users@lists.mcs.anl.gov><br>
<b>Sent:</b> Wednesday, August 1, 2018 2:42:36 AM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> Re: [Nek5000-users] Impose velocity BC on the wall</font>
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<div class="x_moz-cite-prefix">Hi,<br>
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if I am not mistaken, 'W' will always impose zero velocity. You may want to use 'v' instead. If you set zero velocity, it will behave like a wall.<br>
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In addition, there are several things you should change:<br>
1) you should do this in the userbc subroutine that is called once for each point on the boundary where it needs a value (so you don't have to write the loop yourself).<br>
2) there you need to set the variables ux, uy, uz instead of vx, vy, vz. Probably similar to what you do for inflow.<br>
3) be careful checking equalities with floating point numbers, in some cases you could have y very small but non zero.<br>
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Guillaume<br>
<br>
Le 01/08/2018 à 07:01, <a class="x_moz-txt-link-abbreviated" href="mailto:nek5000-users@lists.mcs.anl.gov">
nek5000-users@lists.mcs.anl.gov</a> a écrit :<br>
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<p style="margin-top:0; margin-bottom:0">Dear Nek users,</p>
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<p style="margin-top:0; margin-bottom:0">I am trying to impose a periodic velocity to simulation blowing and suction on a flat plate. The current inlet has a specified velocity whereas the top and outlet are specified as 'O'. The bottom is wall, 'W'. Does anyone
has any experience of specifing a temporally periodic velocity on a narrow strip of the wall? I tried to define this velocity in the usrchk like,</p>
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<p style="margin-top:0; margin-bottom:0">do i = 1, n </p>
<p style="margin-top:0; margin-bottom:0"> x = xm1(...)</p>
<p style="margin-top:0; margin-bottom:0"> y = ym1(...)</p>
<p style="margin-top:0; margin-bottom:0"> IF (y .eq. 0) then</p>
<p style="margin-top:0; margin-bottom:0"> if(x.LT... .and. x.GT...) then</p>
<p style="margin-top:0; margin-bottom:0"> vy (...)= ...</p>
<p style="margin-top:0; margin-bottom:0"> endif</p>
<p style="margin-top:0; margin-bottom:0"> ENDIF</p>
<p style="margin-top:0; margin-bottom:0">enddo</p>
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<p style="margin-top:0; margin-bottom:0">But this does not work. Could anyone give me some suggestions please?</p>
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<p style="margin-top:0; margin-bottom:0">Thanks in advance</p>
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