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<p style="margin-top:0; margin-bottom:0">Dear Juan Pablo,</p>
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<p style="margin-top:0; margin-bottom:0">The documentation I pointed you to is for constant density Boussinesq and the change in density to which I refer is the first-order perturbation that sets up the free convection. (Otherwise, you have no natural convection.)</p>
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<p style="margin-top:0; margin-bottom:0">If you have outflow conditions you will need to do as suggested in that document.</p>
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<p style="margin-top:0; margin-bottom:0">If you don't have outflow conditions then there is something else going on.</p>
<p style="margin-top:0; margin-bottom:0">Since you talk about vortices leaving the domain I was assuming you have outflow, but maybe that's not the case.</p>
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<p style="margin-top:0; margin-bottom:0">If you'd like, feel free to send me the case files off-list and I can take a look.</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" color="#000000" style="font-size:11pt"><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, December 27, 2017 7:28:25 PM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> Re: [Nek5000-users] Set gradient and/or pressure at outlet</font>
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<div dir="ltr">Thanks Paul for the answer. Yes, I'm using <span style="font-size:12.8px">Boussinesq approximation, but using incompresible equations, there are no stratification in the density, like the equations you mention. But, anyway, I'm more interested
in setting the spatial gradient equal to cero in the boundary. ¿How can I achieve that?</span>
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<div><span style="font-size:12.8px">dUy/dy=0</span><span style="font-size:12.8px"><br>
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<div><span style="font-size:12.8px">dTEMP/dy=0</span><span style="font-size:12.8px"><br>
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<div><span style="font-size:12.8px">Thanks a lot,</span></div>
<div><span style="font-size:12.8px">Juan Pablo.</span></div>
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