<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Thanks Jan !<div class=""><br class=""></div><div class="">so it is confirmed that the tilmestep is based exclusively on the velocity field ?</div><div class="">how do people make sure that the passive scalars do not blow up ? </div><div class="">anybody ?</div><div class=""><br class=""></div><div class="">any help is greatly appreciated !!</div><div class="">agnese</div><div class=""><br class=""></div><div class=""><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Agnese Seminara</div><div class=""><div class="">--------------------------------</div><div class="">CNRS</div><div class="">Institut de Physique de Nice</div><div class="">Parc Valrose </div><div class="">avenue J Vallot</div><div class="">06108 Nice, France</div><div class=""><span style="color: rgb(38, 48, 51); font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);" class="">+33 (0) 492 076 775</span></div><div class=""><a href="http://sites.unice.fr/site/aseminara/" class="">http://sites.unice.fr/site/aseminara/</a></div></div></div></div></div>
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<br class=""><div><blockquote type="cite" class=""><div class="">On Jun 13, 2017, at 7:00 PM, <a href="mailto:nek5000-users-request@lists.mcs.anl.gov" class="">nek5000-users-request@lists.mcs.anl.gov</a> wrote:</div><br class="Apple-interchange-newline"><div class="">Send Nek5000-users mailing list submissions to<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><a href="mailto:nek5000-users@lists.mcs.anl.gov" class="">nek5000-users@lists.mcs.anl.gov</a><br class=""><br class="">To subscribe or unsubscribe via the World Wide Web, visit<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users<br class="">or, via email, send a message with subject or body 'help' to<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>nek5000-users-request@lists.mcs.anl.gov<br class=""><br class="">You can reach the person managing the list at<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>nek5000-users-owner@lists.mcs.anl.gov<br class=""><br class="">When replying, please edit your Subject line so it is more specific<br class="">than "Re: Contents of Nek5000-users digest..."<br class="">Today's Topics:<br class=""><br class=""> 1. Re: Courant for passive scalar ? (nek5000-users@lists.mcs.anl.gov)<br class=""> 2. prenek (nek5000-users@lists.mcs.anl.gov)<br class=""><br class=""><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">From: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">nek5000-users@lists.mcs.anl.gov<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">Subject: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class=""><b class="">Re: [Nek5000-users] Courant for passive scalar ?</b><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">Date: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">June 12, 2017 at 8:00:26 PM GMT+2<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">nek5000-users@lists.mcs.anl.gov<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">Reply-To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">nek5000-users@lists.mcs.anl.gov<br class=""></span></div><br class=""><br class=""><meta http-equiv="content-type" content="text/html; charset=utf-8" class=""><div dir="auto" class=""><div class=""></div><div class="">Hi,</div><div class="">I haven' t tried this myself, but I guess you could write a subroutine that calculates the maximum timestep from the scalar field and sets dt accordingly. Then simple call the routine from userchk.</div><div class=""><br class=""></div><div class="">Best,</div><div class="">Jan</div><div class=""><br class="">Am 12.06.2017 um 18:15 schrieb <a href="mailto:nek5000-users@lists.mcs.anl.gov" class="">nek5000-users@lists.mcs.anl.gov</a>:<br class=""><br class=""></div><blockquote type="cite" class=""><div class=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class="">Dear Neks<div class=""><br class=""></div><div class="">I am running a simulation of a channel, with a passive scalar. Using diffusivity=viscosity, the velocity field converges nicely, whereas the passive scalar blows up at some random point down the simulation. Reynolds number is 10 000 so its in the turbulent regime.</div><div class=""><br class=""></div><div class="">I suspect this is due to the fact that the passive scalar is intermittent, so sometimes large fluctuations will occur, totally uncorrelated to velocity fluctuations. to avoid the code to blow up, one would need to setup the timestep based on a courant criterion for the scalar, and not for the velocity. </div><div class=""><br class=""></div><div class="">has this already been implemented ?</div><div class="">or how do people avoid this ?</div><div class=""><br class=""></div><div class="">any suggestion is more than welcome.</div><div class="">thanks</div><div class="">Agnese</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""><div class="">
<div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Agnese Seminara</div><div class=""><div class="">--------------------------------</div><div class="">CNRS</div><div class="">Institut de Physique de Nice</div><div class="">Parc Valrose </div><div class="">avenue J Vallot</div><div class="">06108 Nice, France</div><div class=""><span style="color: rgb(38, 48, 51); font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);" class="">+33 (0) 492 076 775</span></div><div class=""><a href="http://sites.unice.fr/site/aseminara/" class="">http://sites.unice.fr/site/aseminara/</a></div></div></div></div></div>
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<br class=""></div></div></blockquote><blockquote type="cite" class=""><div class=""><span class="">_______________________________________________</span><br class=""><span class="">Nek5000-users mailing list</span><br class=""><span class=""><a href="mailto:Nek5000-users@lists.mcs.anl.gov" class="">Nek5000-users@lists.mcs.anl.gov</a></span><br class=""><span class=""><a href="https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users" class="">https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users</a></span><br class=""></div></blockquote></div><br class=""><br class=""><br class=""><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">From: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">nek5000-users@lists.mcs.anl.gov<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">Subject: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class=""><b class="">[Nek5000-users] prenek</b><br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">Date: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">June 13, 2017 at 12:12:49 PM GMT+2<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">nek5000-users@lists.mcs.anl.gov<br class=""></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;" class=""><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif; color:rgba(127, 127, 127, 1.0);" class=""><b class="">Reply-To: </b></span><span style="font-family: -webkit-system-font, Helvetica Neue, Helvetica, sans-serif;" class="">nek5000-users@lists.mcs.anl.gov<br class=""></span></div><br class=""><br class=""><div dir="ltr" class="">Hi nek,<div class=""><br class=""></div><div class="">I have a 2D mesh. When I used global refine function, the errors occurred. do you know why?</div><div class=""><br class=""></div><div class=""><div class=""> OCT/Multi-SPLIT</div><div class="">quad or multi-split? (q/m)</div><div class="">Number of elements after OctSplit operation: 7680</div><div class="">Are you sure you want to split (y/n)?</div><div class=""> inside gencen 7680 F 4</div><div class=""> done gencen 7680</div><div class=""> start locglob_lexico: 4 7680 30720 2.00000009E-03</div><div class=""> locglob: 1 1 30720</div><div class=""> locglob: 2 3664 30720</div><div class=""> locglob: 1 7761 30720</div><div class=""> locglob: 2 7761 30720</div><div class=""> Performing unique_vertex2 self_chk 30720</div><div class=""> done locglob_lexico: 7761 7761 30720 4</div><div class=""> Performing makecell self_chk 30720</div><div class=""><br class=""></div><div class=""> RMIN: 0.153545E-03</div><div class=""> EPS,RMIN: 0.500000E-01 0.153545E-03</div><div class=""> I/O Error: No String Terminator sent to PRS</div><div class=""> zeroing y: 1 82 -0.75715434E-10</div><div class=""> I/O Error: No String Terminator sent to PRS</div><div class=""> zeroing y: 4 82 -0.14778734E-11</div><div class=""> I/O Error: No String Terminator sent to PRS</div><div class=""> zeroing y: 4 83 0.72759583E-10</div><div class=""> I/O Error: No String Terminator sent to PRS</div><div class=""> zeroing y: 4 123 0.15279482E-09</div></div><div class="">......</div><div class=""><br class=""></div><div class="">Does it mean my mesh is still not right?</div></div>
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