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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 12pt;">Hi Ilias,<br>
<br>
As I mentioned to you earlier, for the case when you subdomain integration consists of whole elements, I would do the simplest<br>
<br>
dimension ybm1(lx1*ly1*lz1), rmask(lx1*ly1*lz1,lelt)<br>
<br>
nxyz = nx1*ny1*nz1<br>
ntot = nxzy*nelt<br>
do e=1,nelt <br>
call rzero(rmask,ntot)<br>
call col3(ybm1,bm1,nxyz)<br>
yavg = vlsum(ybm1,nxyz)<br>
yavg = yavg/vlsum(ym1,nxyz)<br>
if (yavg.gt.y_something) call rone(rmask(1,1,1,e),nxyz)<br>
enddo<br>
<br>
and then use glsc3 with arguments of bm1, your quantity on GLL mesh, and created rmask.<br>
<br>
Note that the above approach with modification will work even for the case of the integration subdomain boundary cutting through the elements but you need to use every GLL's ym1 instead of yavg -- be aware that the spectral convergence of this integration with
increase of polynomial order will be affected since it is equivalent to integration of a step/discontinuous function inside an element...<br>
<br>
Note also that if the integration subdomain is much smaller than the whole domain, you could compute the collocation with your quantity and bm1 inside the above loop and do summation yourself
<br>
<br>
Aleks<br>
<br>
<br>
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<div style="direction: ltr;" id="divRpF650457"><font face="Tahoma" color="#000000" size="2"><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> Thursday, October 29, 2015 1:16 PM<br>
<b>To:</b> nek5000-users@lists.mcs.anl.gov<br>
<b>Subject:</b> [Nek5000-users] energy dissipation over a subdomain<br>
</font><br>
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<div dir="ltr">Dear neks!
<div><br>
</div>
<div>I would like to compute kinetic energy dissipation over different subdomains.</div>
<div><br>
</div>
<div>It involves the calculation of the dissipation itself in GLL points,</div>
<div>and integration over some domain.</div>
<div><br>
</div>
<div>I understand now that it is more accurate to involve whole number of elements </div>
<div>for integration, </div>
<div>and that for computation of the integral over</div>
<div>a subdomain one can use a mask (of 1s and 0es) over the whole domain,</div>
<div>and after that to use global scalar product like glsc3.</div>
<div><br>
</div>
<div>Are there the implementations of these ideas?</div>
<div>first of all, the creation of a mask, based on geometrical constructions like</div>
<div>
<div> IF (Y.gt.something) THEN</div>
</div>
<div>...</div>
<div><br>
</div>
<div>and also if somebody has already a procedure of kinetic energy dissipation,</div>
<div>though here it is more strait: calculation of of velocity gradient and contraction of</div>
<div>its multiplication with itself,</div>
<div><br>
</div>
<div>Thank you, Ilias</div>
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