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Hi Andrew,
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<div>The projection routines are currently being overhauled, but the general strategy is:</div>
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<div> Number of projections controlled by p93 and mxprev in SIZE. </div>
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<div> p94 > 0: start projecting velocity/temp after step p94</div>
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<div> p95 > 0: start projecting pressure after step 95</div>
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<div>I typically set p94 and p95 to 5</div>
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<div>I set mxprev and p93 to 20, but sometimes to a higher value.</div>
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<div>I used to occasionally to to much higher than 20 (say, 80), but in a recent</div>
<div>rewrite and effort to make projection more robust I slowed the projection</div>
<div>step down with too much work, so another rewrite is due soon.</div>
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<div>Paul</div>
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<div>PS - note that certain combinations of run parameters don't support</div>
<div>projection or potentially blow up. Set p94=0 in this case and retry.</div>
<div>There was a bug that was fixed about 6 weeks back---it may have cured</div>
<div>some of the cases that users were running into.</div>
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<div id="divRpF765626" 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> Monday, June 27, 2016 3:17 AM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> [Nek5000-users] Projection technique's parameters<br>
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<div dir="ltr"><span lang="en"><span>Hi Neks,<br>
<br>
</span></span>My question is about the parameters which manage the projection method in the NEK5000: p93, p94 and p95. How can the correct values be selected for these parameters to obtain the better performance depending on the nature of simulation: laminar
/ turbulent, convection / diffusion, time step?<br>
<br>
<span lang="en">Thank you for any suggestion, <br>
</span><span lang="en">Andrew</span><br>
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