<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Let me explain slightly better. For Direct Numerical Simulations (DNS), all the scales of turbulence are computed directly and no scales are modeled. Thus, no turbulence model is needed, you will get turbulence naturally as the direct solution of equations. Usually, some initial perturbation of the flow field is recommended to get the statistically-converged turbulence faster. For Large Eddy Simulations (LES), only the largest scales are computed directly, and the smaller scales are modeled (with the so-called sub grid-scale (SGS) models). SGS models for LES are available in Nek5000, including classical Smagorinsky and dynamic Smagorinsky models (they are in a TurbChannel example). For Reynolds Averaged Navier Stokes (RANS) simulations, all scales of motion are modeled. RANS models for Nek5000 are still in an exploratory stage and I believe are not yet part of the repo suite.<div><br></div><div>Please, let me know if you have any further questions.</div><div><br></div><div>Best regards,</div><div>Yulia</div><div><br><div><div>On Jul 6, 2016, at 4:42 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 lang="EN-US" link="blue" vlink="purple" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 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;"><div class="WordSection1" style="page: WordSection1;"><div style="margin: 0in 0in 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif;"><span style="font-size: 12pt; font-family: 'Times New Roman', serif;">I am trying to generate a set of DNS data for a turbulent channel flow, and I am currently trying to build my case in prex. When I try to select “Turbulence Model”, it says “Turbulence Models not yet implemented”. How can this be the case if there is already an example turbulent channel flow included with Nek5000?<o:p></o:p></span></div></div>_______________________________________________<br>Nek5000-users mailing list<br><a href="mailto:Nek5000-users@lists.mcs.anl.gov" style="color: purple; text-decoration: underline;">Nek5000-users@lists.mcs.anl.gov</a><br><a href="https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users" style="color: purple; text-decoration: underline;">https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users</a></div></blockquote></div><br></div></body></html>