https://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&feed=atom&action=historyTurbulence free-stream boundary conditions - Revision history2024-03-28T16:18:26ZRevision history for this page on the wikiMediaWiki 1.16.5https://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=22693&oldid=prevDmoroian at 11:59, 15 January 20142014-01-15T11:59:40Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = \frac{\sqrt{k}}{l}</math></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = \frac{\sqrt{k}}{l}</math></div></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Please note that some CFD codes, Fluent, Phoenics and CFD-ACE for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Please note that some CFD codes, Fluent, Phoenics and CFD-ACE for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = C_\mu^{-\frac{1}{4}} \, \frac{\sqrt{k}}{l}</math></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = C_\mu^{-\frac{1}{4}} \, \frac{\sqrt{k}}{l}</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]].</ins></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the eddy viscosity ratio====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the eddy viscosity ratio====</div></td></tr>
</table>Dmoroianhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=17009&oldid=prevPeter: Reverted edits by Tikulju (talk) to last revision by Peter2013-02-06T18:15:13Z<p>Reverted edits by <a href="/Wiki/Special:Contributions/Tikulju" title="Special:Contributions/Tikulju">Tikulju</a> (<a href="/W/index.php?title=User_talk:Tikulju&action=edit&redlink=1" class="new" title="User talk:Tikulju (page does not exist)">talk</a>) to last revision by <a href="/Wiki/User:Peter" title="User:Peter">Peter</a></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>:<math>\omega = <del class="diffchange diffchange-inline">C_\mu</del>\frac{\sqrt{k}}{l}</math></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>:<math>\omega = \frac{\sqrt{k}}{l}</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td></tr>
</table>Peterhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=17007&oldid=prevTikulju at 14:09, 6 February 20132013-02-06T14:09:04Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>:<math>\omega = \frac{\sqrt{k}}{l}</math></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>:<math>\omega = <ins class="diffchange diffchange-inline">C_\mu</ins>\frac{\sqrt{k}}{l}</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td></tr>
</table>Tikuljuhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=13009&oldid=prevPeter: corrected errors2011-06-20T13:20:45Z<p>corrected errors</p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>:<math>\epsilon = \frac{k^\frac{3}{2}}{l}</math></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>:<math>\epsilon = <ins class="diffchange diffchange-inline">C_\mu \, </ins>\frac{k^\frac{3}{2}}{l}</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>:<math>\omega = \frac{\sqrt{k}}{<del class="diffchange diffchange-inline">C_\mu \, </del>l}</math></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>:<math>\omega = \frac{\sqrt{k}}{l}</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td></tr>
</table>Peterhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=12994&oldid=prevPeter: Added more codes with other length scale definition2011-06-15T20:13:47Z<p>Added more codes with other length scale definition</p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Please note that some CFD codes, Fluent for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Please note that some CFD codes, Fluent<ins class="diffchange diffchange-inline">, Phoenics and CFD-ACE </ins>for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\epsilon = C_\mu^\frac{3}{4} \, \frac{k^\frac{3}{2}}{l}</math></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\epsilon = C_\mu^\frac{3}{4} \, \frac{k^\frac{3}{2}}{l}</math></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Please note that some CFD codes, Fluent for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Please note that some CFD codes, Fluent<ins class="diffchange diffchange-inline">, Phoenics and CFD-ACE </ins>for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = C_\mu^{-\frac{1}{4}} \, \frac{\sqrt{k}}{l}</math></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = C_\mu^{-\frac{1}{4}} \, \frac{\sqrt{k}}{l}</math></div></td></tr>
</table>Peterhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=12985&oldid=prevPeter: Changed to most used turbulence length scale definition and added a note about the other "Fluent" mixing-length version2011-06-15T10:52:57Z<p>Changed to most used turbulence length scale definition and added a note about the other "Fluent" mixing-length version</p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">:<math>\epsilon = \frac{k^\frac{3}{2}}{l}</math></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"><math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Please note that some CFD codes, Fluent for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\epsilon = C_\mu^\frac{3}{4} \, \frac{k^\frac{3}{2}}{l}</math></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\epsilon = C_\mu^\frac{3}{4} \, \frac{k^\frac{3}{2}}{l}</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math><del class="diffchange diffchange-inline">, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the eddy viscosity ratio====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the eddy viscosity ratio====</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the turbulence length scale====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>:<math>\omega = <del class="diffchange diffchange-inline">C_\mu^{-\frac{1}{4}} \, </del>\frac{\sqrt{k}}{l}</math></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>:<math>\omega = \frac{\sqrt{k}}{<ins class="diffchange diffchange-inline">C_\mu \, </ins>l}</math></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>C_\mu</math> is a turbulence model constant which usually has a value of <math>0.09</math>, <math>k</math> is the turbulent energy and <math>l</math> is the [[turbulent length scale]]</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Please note that some CFD codes, Fluent for example, uses a different length-scale definition based on the mixing-length, and therefore the following formula should be used:</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">:<math>\omega = C_\mu^{-\frac{1}{4}} \, \frac{\sqrt{k}}{l}</math></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the eddy viscosity ratio====</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>====From the eddy viscosity ratio====</div></td></tr>
</table>Peterhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=9089&oldid=prevToh24: /* Formulas for computing the turbulence model variables */2008-05-19T16:30:56Z<p><span class="autocomment">Formulas for computing the turbulence model variables</span></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>==Formulas for computing the turbulence model variables==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>==Formulas for computing the turbulence model variables==</div></td></tr>
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<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Once an appropriate turbulence intensity and <del class="diffchange diffchange-inline">turbulent </del>length scale or eddy viscosity ratio <del class="diffchange diffchange-inline">has </del>been estimated the primitive turbulence model variables can be computed from the following formulas<del class="diffchange diffchange-inline">:</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Once an appropriate turbulence intensity and <ins class="diffchange diffchange-inline">turbulence </ins>length scale or eddy viscosity ratio <ins class="diffchange diffchange-inline">have </ins>been estimated <ins class="diffchange diffchange-inline">or measured, </ins>the primitive turbulence model variables can be computed from the following formulas<ins class="diffchange diffchange-inline">. Some codes may not require the <math>C_\mu</math> constant so it is a good idea to check the user manual if possible.</ins></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>===Modified turbulent viscosity===</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>===Modified turbulent viscosity===</div></td></tr>
</table>Toh24https://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=9085&oldid=prevTohoughton: /* From the turbulence intensity and length scale */2008-05-15T12:43:52Z<p><span class="autocomment">From the turbulence intensity and length scale</span></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>U</math> is the mean flow velocity, <math>I</math> is the [[turbulence intensity]] and <math>l</math> is the [[turbulent length scale]].</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Where <math>U</math> is the mean flow velocity, <math>I</math> is the [[turbulence intensity]] and <math>l</math> is the [[turbulent length scale]].</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Ideally <del class="diffchange diffchange-inline">in </del>the Spalart-Allmaras model <math>\tilde{\nu}=0</math>, but some solvers can have problem with that so <math>\tilde{\nu}<=\frac{\nu}{2}</math> can be used. This is if the trip term is used to "start up" the model. A convenient option is to set <math>\tilde{\nu}=5{\nu}</math> in the freestream. The model then provides fully turbulent results and any regions like boundary layers that contain shear become fully turbulent.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Ideally <ins class="diffchange diffchange-inline">with </ins>the <ins class="diffchange diffchange-inline">[[Spalart-Allmaras_model|</ins>Spalart-Allmaras model<ins class="diffchange diffchange-inline">]] </ins><math>\tilde{\nu}=0</math>, but some solvers can have problem with that so <math>\tilde{\nu}<=\frac{\nu}{2}</math> can be used. This is if the trip term is used to "start up" the model. A convenient option is to set <math>\tilde{\nu}=5{\nu}</math> in the freestream. The model then provides fully turbulent results and any regions like boundary layers that contain shear become fully turbulent.</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>===Turbulent energy===</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>===Turbulent energy===</div></td></tr>
</table>Tohoughtonhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=9082&oldid=prevTohoughton: /* From the turbulent length scale */2008-05-15T10:22:49Z<p><span class="autocomment">From the turbulent length scale</span></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The specific turbulent dissipation rate, <math>\omega</math>, can be computed using the following formulas:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The specific turbulent dissipation rate, <math>\omega</math>, can be computed using the following formulas:</div></td></tr>
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<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>====From the <del class="diffchange diffchange-inline">turbulent </del>length scale====</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>====From the <ins class="diffchange diffchange-inline">turbulence </ins>length scale====</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = C_\mu^{-\frac{1}{4}} \, \frac{\sqrt{k}}{l}</math></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\omega = C_\mu^{-\frac{1}{4}} \, \frac{\sqrt{k}}{l}</math></div></td></tr>
</table>Tohoughtonhttps://cfd-online.com/W/index.php?title=Turbulence_free-stream_boundary_conditions&diff=9081&oldid=prevTohoughton: /* Dissipation rate */2008-05-15T10:22:38Z<p><span class="autocomment">Dissipation rate</span></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The turbulent dissipation rate, <math>\epsilon</math>, can be computed using the following formulas:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The turbulent dissipation rate, <math>\epsilon</math>, can be computed using the following formulas:</div></td></tr>
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<tr><td class='diff-marker'>-</td><td style="background: #ffa; color:black; font-size: smaller;"><div>====From the <del class="diffchange diffchange-inline">turbulent </del>length scale====</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>====From the <ins class="diffchange diffchange-inline">turbulence </ins>length scale====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\epsilon = C_\mu^\frac{3}{4} \, \frac{k^\frac{3}{2}}{l}</math></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>:<math>\epsilon = C_\mu^\frac{3}{4} \, \frac{k^\frac{3}{2}}{l}</math></div></td></tr>
</table>Tohoughton