<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">Dear Paul</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)"><span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">thanks for your quick answer. We thought we were imposing the Prandtl number since in the </span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">web we found the following information</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)"><span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">P008 CONDUCT conductivity for the case of constant properties (see</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)"> parameter P030) if <0, it defines the Prandtl number</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)"><span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">Is the previous information not correct?</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">Should we fix the conductivity to -750*0.7 or to 750*0.7 ?</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)"><span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">Concerning the boundary conditions we are indeed using periodic boundary conditions. </span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">However, we are not interested in the</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">constant temperature case. We were using it for testing (since we errouneously thought it </span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">was easier). In the end we will impose</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">the heat flux.</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)"><span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">Thanks again</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)"><span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">Best Regards,</span><br style="padding:0px;margin:0px;font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">
<span style="font-family:monospace,fixed;font-size:13.333333015441895px;background-color:rgb(255,255,255)">Alex</span><br><br><div class="gmail_quote">2013/2/13 <span dir="ltr"><<a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.gov</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Hi Alex,<br>
<br>
I see you have ifadv set to T, which is correct.<br>
<br>
However, I also see that your conductivity is -.7, which<br>
implies your Peclet number is 0.7 ---- (assuming your Reynolds number is 750). Is this what you want ?<br>
<br>
Also, are you using periodic boundary conditions?<br>
If so, it takes a bit of care to get meaningful<br>
forcing conditions, particularly for the fixed-temperature<br>
boundary condition. (This condition leads to determination<br>
of an eigenvalue to find the fully-developed flow conditions,<br>
which have a bulk temperature scaling like exp(-lambda x).<br>
I can point you to some techniques for developing such conditions if you'd like.)<br>
<br>
Paul<div><div class="h5"><br>
<br>
<br>
<br>
On Wed, 13 Feb 2013, <a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.<u></u>gov</a> wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Dear all<br>
<br>
we are trying to make calculations of turbulent heat transfer in a<br>
pipe. Everything seems to work fine<br>
with the velocity field, however this is not the case for the<br>
temperature. It seems as if the convection<br>
for the temperature equation is switched off. So, we obtain a<br>
turbulent velocity distribution but a laminar temperature<br>
distribution.<br>
<br>
We have tried several thermal boundary condtions and at the moment we<br>
are just fixing the temperature at the wall<br>
T=0 and adding a heat source qvol=1. In the following we add details<br>
of the case.<br>
<br>
Thanks for your help<br>
<br>
Regards,<br>
Alex<br>
<br>
rea file<br>
****** PARAMETERS *****<br>
2.6099999 NEKTON VERSION<br>
3 DIMENSIONAL RUN<br>
103 PARAMETERS FOLLOW<br>
1.00000 p001 DENSITY<br>
-750. p002 VISCOS<br>
0.00000 p003<br>
0.00000 p004<br>
0.00000 p005<br>
0.00000 p006<br>
1.00000 p007 RHOCP<br>
-0.7 p008 CONDUCT<br>
[...]<br>
13 LOGICAL SWITCHES FOLLOW<br>
T IFFLOW<br>
T IFHEAT<br>
T IFTRAN<br>
T T F F F F F F F F F IFNAV & IFADVC (convection in P.S. fields)<br>
F F T T T T T T T T T T IFTMSH (IF mesh for this field is T mesh)<br>
F IFAXIS<br>
F IFSTRS<br>
F IFSPLIT<br>
F IFMGRID<br>
F IFMODEL<br>
F IFKEPS<br>
F IFMVBD<br>
F IFCHAR<br>
[...]<br>
<br>
usr file<br>
[...]<br>
c-----------------------------<br>
------------------------------<u></u>------------<br>
subroutine userf (ix,iy,iz,ieg)<br>
include 'SIZE'<br>
include 'TOTAL'<br>
include 'NEKUSE'<br>
<br>
ffx = 0.0<br>
ffy = 0.0<br>
ffz = 2.0<br>
<br>
return<br>
end<br>
c-----------------------------<u></u>------------------------------<u></u>------------<br>
subroutine userq (ix,iy,iz,ieg)<br>
include 'SIZE'<br>
include 'TOTAL'<br>
include 'NEKUSE'<br>
<br>
qvol = 1.0<br>
source = 0.0<br>
<br>
return<br>
end<br>
c-----------------------------<u></u>------------------------------<u></u>------------<br>
[...]<br>
<br>
</blockquote></div></div>
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</blockquote></div><br>