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<p>Dear Paul,</p>
<p><br>
</p>
<p>Indeed thanks for the input However, the volume average velocity
still tends to zero and as a consequence the rescaling routine
tries to compensate making the code unstable until it diverges.
The reason why the volume average velocity tends to zero could
simply be because the flow relaminarizes in the absence of
fluctuations in the prescribed inlet. From my understanding the
recycling routine only rescales the flow to a target mean velocity
without adding fluctuations.</p>
<p>To be sure of that change of dynamic I set up a simulation with a
(1/7)th velocity profile at the inlet (same code but without
recycling) convinced that the flow would laminarize and tend to a
"blasius-like" profile. To my surprise the flow remained steady.</p>
<p>Finally as I want to use a dynamic Smagorinsky model for this
project I set the filtering to none and variable properties to
TRUE however it seems that there is a division by zero which I
couldn't trace back in the source code.<br>
</p>
<p><br>
</p>
<p>Just after starting to compute the eddy viscosity :</p>
<p><br>
</p>
<p> Calculating eddy visosity<br>
flt amp 0.0000 0.0000 0.0000 0.0000 0.0000 0.0500 0.5000 0.9500<br>
flt trn 1.0000 1.0000 1.0000 1.0000 1.0000 0.9500 0.5000 0.0500<br>
forrtl: severe (71): integer divide by zero<br>
Image PC Routine
Line Source <br>
nek5000 00000000008CF105 Unknown
Unknown Unknown<br>
libpthread-2.17.s 00002B44DF7BD370 Unknown
Unknown Unknown<br>
nek5000 00000000005D70BE Unknown
Unknown Unknown<br>
nek5000 0000000000408121 Unknown
Unknown Unknown<br>
nek5000 0000000000404D3F Unknown
Unknown Unknown<br>
nek5000 000000000040F572 Unknown
Unknown Unknown<br>
nek5000 000000000040E0DF Unknown
Unknown Unknown<br>
nek5000 0000000000404A1E Unknown
Unknown Unknown<br>
libc-2.17.so 00002B44DFCEDB35 __libc_start_main
Unknown Unknown<br>
nek5000 0000000000404929 Unknown
Unknown Unknown<br>
<br>
</p>
<br>
Sincerely,<br>
Armand.<br>
<br>
<div class="moz-cite-prefix">Le 07/06/2018 à 15:43,
<a class="moz-txt-link-abbreviated" href="mailto:nek5000-users@lists.mcs.anl.gov">nek5000-users@lists.mcs.anl.gov</a> a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:mailman.3512.1528379038.86639.nek5000-users@lists.mcs.anl.gov">
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charset=windows-1252">
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style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;"
dir="ltr">
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Dear Armand,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">The attached .usr file
seems to work ok... just a few</p>
<p style="margin-top:0;margin-bottom:0">small modifications to
the .usr file you provided.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">I think the main issue
was the declaration of some of the</p>
<p style="margin-top:0;margin-bottom:0">variables in useric.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Best,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Paul</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b>
Nek5000-users <a class="moz-txt-link-rfc2396E" href="mailto:nek5000-users-bounces@lists.mcs.anl.gov"><nek5000-users-bounces@lists.mcs.anl.gov></a>
on behalf of <a class="moz-txt-link-abbreviated" href="mailto:nek5000-users@lists.mcs.anl.gov">nek5000-users@lists.mcs.anl.gov</a>
<a class="moz-txt-link-rfc2396E" href="mailto:nek5000-users@lists.mcs.anl.gov"><nek5000-users@lists.mcs.anl.gov></a><br>
<b>Sent:</b> Thursday, June 7, 2018 3:51:09 AM<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:nek5000-users@lists.mcs.anl.gov">nek5000-users@lists.mcs.anl.gov</a><br>
<b>Subject:</b> [Nek5000-users] Initial Condition &
Recycling</font>
<div> </div>
</div>
<div class="BodyFragment"><font size="2"><span
style="font-size:11pt;">
<div class="PlainText">Dear All,<br>
<br>
<br>
In an attempt to simulate an established turbulent flow
over a flat <br>
plate with a recycling method for the inlet, it has to my
attention that <br>
a (1/7)th Power Law would be suitable as an initial
condition. However <br>
the solver divergences and I think I know why.<br>
<br>
Here the layout of the recycling procedure :<br>
<br>
1. call set_inflow_fpt in userchk<br>
<br>
2. If it is the 1st call then call setp_inflow_fpt_setup<br>
<br>
3. call rescale_fpt (which rescales the copied field to a
user specified <br>
mean velocity ubar)<br>
<br>
4.In the rescale_fpt routine we call get_flux_and_area
which gives the <br>
flux and area of a face with cbc == 'v ' so a user
specified velocity <br>
boundary condition.<br>
<br>
4. a) As the initial condition is wrong once that routine
sums the flux <br>
on the boundary it returns zero in this case and the
variable scale <br>
which is divided by the latter returns infinity !<br>
<br>
<br>
However I set the initial conditions as in many other
examples, such as <br>
the turbInflow. Would have an insight that could lead me
to a solution ?<br>
<br>
<br>
Please find attached the related files.<br>
<br>
<br>
Sincerely,<br>
<br>
Armand, ONERA - The French Aerospace Lab.<br>
<br>
<br>
</div>
</span></font></div>
<br>
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