<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Can you elaborate on the 512^3 case? it is impressive you are getting close with 32^3 and some filtering<div>I was wondering :</div><div>(1) what if you turn off filtering with 32^3 (i.e. set f=0), the question here if filtering is significantly contributing to the dissipation rate. if it does not make a big difference then I would say your LES with 32^3 and f=0.05 is pretty good. </div><div>(2) how does the time history in all cases compare to Brachet et al. (see my previous note) at the same Re. </div><div><br></div><div>Ammar</div><div><br><div><div>On Dec 8, 2012, at 3:01 PM, <a href="mailto:nek5000-users@lists.mcs.anl.gov">nek5000-users@lists.mcs.anl.gov</a> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Your results make sense to me. Note that you are not really "capturing" peak dissipation rate with filtering. <div>you are only supplementing the resolved dissipation on a given grid by artificially damping energy. that's why you get higher peak with f=0.05 and N=14^3 relative to f=0 and N=14^3 </div><div>I wonder how much resolution N^3 you need (with f=0) to truly capture the peak dissipation rate? </div><div><br></div><div>In order to better judge your simulations you should compare DNS (f=0) and LES f=nonzero for gradually increased resolution N^3 </div><div><br></div><div>if DNS is expensive , good news DNS is already been done , Check Brachet et al JFM article <a href="http://journals.cambridge.org/action/displayJournal?jid=FLM" title="Journal of Fluid Mechanics" style="margin: 0px; padding: 0px; border: 0px; outline: 0px; font-weight: normal; font-style: normal; font-size: 11px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; vertical-align: baseline; color: rgb(4, 89, 137); text-decoration: none; line-height: 14px; font-variant: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(241, 241, 241); ">Journal of Fluid Mechanics</a><span style="color: rgb(0, 0, 0); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 14px; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(241, 241, 241); display: inline !important; float: none; "> / Volume 130 / </span><span style="color: rgb(0, 0, 0); font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 14px; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(241, 241, 241); display: inline !important; float: none; ">May 1983, pp 411-452</span></div><div>(</div><h2 style="margin: 0px; padding: 5px 0px; border: 0px; outline: 0px; font-weight: bold; font-style: normal; font-size: 11px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; vertical-align: baseline; color: rgb(4, 89, 137); font-variant: normal; letter-spacing: normal; line-height: 15px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(241, 241, 241); "><font color="#336699" size="+1" style="margin: 0px; padding: 0px; border: 0px; outline: 0px; font-weight: inherit; font-style: inherit; font-size: 11px; font-family: inherit; vertical-align: baseline; ">Small-scale structure of the Taylor–Green vortex</font></h2><h3 style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 5px; padding-right: 0px; padding-bottom: 5px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-weight: bold; font-style: normal; font-size: 11px; font-family: verdana, arial, sans-serif; vertical-align: baseline; color: rgb(98, 98, 98); font-variant: normal; letter-spacing: normal; line-height: 15px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(241, 241, 241); position: static; z-index: auto; "><table border="0" align="top" width="95%" style="margin-top: 10px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-weight: normal; font-style: normal; font-size: 11px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; vertical-align: baseline; border-collapse: separate; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; color: rgb(98, 98, 98); font-variant: normal; letter-spacing: normal; line-height: 15px; orphans: 2; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(241, 241, 241); "><tbody style="margin: 0px; padding: 0px; border: 0px; outline: 0px; font-weight: inherit; font-style: inherit; font-size: 11px; font-family: inherit; vertical-align: baseline; "><tr valign="top" style="margin: 0px; padding: 0px; border: 0px; outline: 0px; font-weight: inherit; font-style: inherit; font-size: 11px; font-family: inherit; vertical-align: baseline; "><td style="margin: 0px; padding: 0px; border: 0px; outline: 0px; font-weight: normal; font-style: inherit; font-size: 11px; font-family: 'Arial Unicode MS', Arial, Helvetica, sans-serif; vertical-align: baseline; text-align: left; color: rgb(98, 98, 98); line-height: 1.4em; "><b><b>Marc E. </b> <b>Brachet </b><sup>a1</sup><a href="http://journals.cambridge.org/action/displayAbstract;jsessionid=2541E59358A427C052F22128A3D13BCC.journals?fromPage=online&aid=376272#p1" style="margin: 0px; padding: 0px; border: 0px; outline: 0px; font-weight: inherit; font-style: inherit; font-size: 11px; font-family: inherit; vertical-align: baseline; color: rgb(4, 89, 137); text-decoration: none; "><sup>p1</sup></a></b>, <b><b>Daniel I. </b> <b>Meiron </b><sup>a1</sup></b>, <b><b>Steven A. </b> <b>Orszag </b><sup>a1</sup></b>, <b><b>B. G. </b> <b>Nickel </b><sup>a2</sup></b></td></tr></tbody></table></h3><div>)</div><div><br></div><div><br></div><div> and compare the time history of the dissipation rate</div><div>to what you get at the same Reynolds number. </div><div><br><div><br></div><div><br></div><div>Ammar</div><div><br></div><div><br></div><div><div><br></div><div><br></div><div><br></div><div><br><div><div>On Dec 8, 2012, at 2:36 AM, <a href="mailto:nek5000-users@lists.mcs.anl.gov">nek5000-users@lists.mcs.anl.gov</a> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">Hello<div>I am solving the 3-D Taylor-Green problem as described here </div><div><br></div><div><a href="http://www.dlr.de/as/desktopdefault.aspx/tabid-8170/13999_read-35550/">http://www.dlr.de/as/desktopdefault.aspx/tabid-8170/13999_read-35550/</a></div>
<div><a href="http://www.as.dlr.de/hiocfd/case_c3.5.pdf">C3.5 Direct Numerical Simulation of the Taylor-Green Vortex at Re = 1600</a></div><div><br></div><div>using NEK.</div><div><br></div><div>I use</div><div><br></div>
<div>lx1 = 10</div><div>lx2 = lx1-2</div><div>ldx = 15</div><div><br></div><div>No of elements = 14^3 or 28^3</div><div><br></div><div>The evolution of dissipation rate with time is shown in attached pdf. </div><div><br></div>
<div><div>f=0.0 indicates no filtering and f=0.05 means filter parameter P103.</div></div><div><br></div><div>Use of filter seems to capture peak dissipation rate better but still some difference is seen. The DG results with similar number of dofs in the problem description give good estimate of peak rate. So I expect NEK results to improve further and would like to ask for any advice. Should I try with larger amount of filtering ?</div>
<div><br></div><div>I have attached my SIZE and rea files.</div><div><br></div><div>Thanks</div><div>praveen</div>
<span><box.rea></span><span><diss.pdf></span><span><SIZE></span>_______________________________________________<br>Nek5000-users mailing list<br><a href="mailto:Nek5000-users@lists.mcs.anl.gov">Nek5000-users@lists.mcs.anl.gov</a><br><a href="https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users">https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users</a><br></blockquote></div><br></div></div></div></div>_______________________________________________<br>Nek5000-users mailing list<br><a href="mailto:Nek5000-users@lists.mcs.anl.gov">Nek5000-users@lists.mcs.anl.gov</a><br>https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users<br></blockquote></div><br></div></body></html>