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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 12pt;">Hi Juan,
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<div>At first I would just try truncating the fully de-alised product for all the modes above lx1 since the first lx1 modes are accurately solved<span style="font-size: 12pt;"> for.</span></div>
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<div>Aleks<br>
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<div id="divRpF799224" style="direction: ltr;"><font face="Tahoma" size="2" color="#000000"><b>From:</b> nek5000-users-bounces@lists.mcs.anl.gov [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, March 22, 2017 12:21 PM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> Re: [Nek5000-users] Project a solution onto a polynomial space<br>
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<p>Dear Paul,</p>
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<p>Thank you for answering so quickly. Yes, the polynomial spaces I'm using are the standard Nek5000 basis functions.</p>
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<p>To understand the problem a little better:</p>
<p>I am conducting DNS of a shear flow and I need to compute higher-order velocity moments. I've implemented some subroutines based on the "avg2" and "avg3" subroutines from Nek, but for higher order moments, i.e. <U^3>, <U^2 V>, etc. The problem is that I
need to de-alias the non-linear quantities, i.e. U^3, before doing the averaging. Since the flow is planar, I also take the spanwise average using the "z_average" subroutine.</p>
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<p>I checked out the "convect.f" file to see how dealiasing is applied by mapping onto the finer grid (lxd), but I'm not quite sure how to project these results back onto the original grid.</p>
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<p>Thank you,</p>
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<p>Juan Diego</p>
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