<div dir="ltr">Hello<div><br></div><div style>What type of BC are available for temperature/passive scalar at the outlet of a channel flow ? Can one use the outflow bc 'O' for these scalars ?</div><div style><br></div>
<div style>For scalars, when we specify insulated bc 'I' does this set convective+diffusive flux to be zero ?</div><div style><br></div><div style>Thanks</div><div style>praveen</div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Sat, Oct 12, 2013 at 10:58 PM, Praveen Chandrashekar <span dir="ltr"><<a href="mailto:nek5000@praveen.e4ward.com" target="_blank">nek5000@praveen.e4ward.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi<div>My problem is flow in a 2d channel. The initial condition is zero velocity in the channel and there is an inlet flow. I have a passive scalar which is flowing in through inlet. Initial temperature is zero everywhere. I am having trouble getting initial iterations to converge. I am trying stress formulation and passive scalars for first time and I do not see what is going wrong.</div>
<div><br></div><div><br></div><div><div> Solving for heat</div><div> Solving for fluid F F T</div><div> Temperature/Passive scalar solution</div><div> 1.0000000000000001E-009 p22 1 2</div>
<div> New CG1-tolerance (RINIT*epsm) = 8.4585499354425527E-033 2. 5514287912844953E-033</div><div> 1 1 Helmholtz TEMP F: 8.4585E-20 1.0000E-09 2.8571E-04 0.0000E+00</div><div> 1 Hmholtz TEMP: 0 8.4585E-20 8.4585E-20 1.0000E-09</div>
<div> 1.0000000000000001E-009 p22 1 2</div><div> New CG1-tolerance (RINIT*epsm) = 5.8174583141330990E-032 1. 7860001538991468E-032</div><div> 1 1 Helmholtz PS 1 F: 5.8175E-19 1.0000E-09 2.0000E-03 0.0000E+00</div>
<div> 1 Hmholtz PS 1: 0 5.8175E-19 5.8175E-19 1.0000E-09</div><div> 1 0.0000E+00 6.0799E-03 Heat done</div><div> New CG1(stress)-tolerance (RINIT*epsm) = 6.9206392325228944E-014 4. 2096427334076814E-033</div>
<div> 0 1.0000E-09 6.9206E-14 1.0000E-09 tol,matmod</div><div> 1 tx3: 1 0.3584E+00 0.1000E-08 0.3584E+00</div><div> 1 tx3: 2 0.2546E+00 0.1000E-08 0.3584E+00</div><div> 1 tx3: 3 0.1905E+00 0.1000E-08 0.3584E+00</div>
<div>.</div><div>.</div><div>.</div><div><div> 1 tx3: 198 0.1080E-02 0.1000E-08 0.3584E+00</div><div> 1 tx3: 199 0.1067E-02 0.1000E-08 0.3584E+00</div><div> 1 tx3: 200 0.1033E-02 0.1000E-08 0.3584E+00</div>
<div> 1 201 Unconverged Helmholtz3/Fluid: rbnorm = 0.103306E-02 0.100000E-08</div><div> 1 1.00000E-07 2.34297E-01 2.34297E-01 1.00000E+00 1 Divergence</div><div> New CG1(stress)-tolerance (RINIT*epsm) = 1.5438583947746548E-016 4. 2096427334076814E-033</div>
<div> 0 1.0000E-09 1.5439E-16 1.0000E-09 tol,matmod</div><div> 1 tx3: 1 0.8855E-02 0.1000E-08 0.8855E-02</div><div> 1 tx3: 2 0.5463E-02 0.1000E-08 0.8855E-02</div><div> 1 tx3: 3 0.5217E-02 0.1000E-08 0.8855E-02</div>
</div><div><br></div><div>Thanks a lot</div><span class="HOEnZb"><font color="#888888"><div>praveen</div></font></span></div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><br><div class="gmail_quote">
On Sat, Oct 12, 2013 at 10:04 PM, <span dir="ltr"><<a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.gov</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Hi Praveen,<br>
<br>
That looks right... As always, it's best to run a test<br>
to verify first.<br>
<div><br>
Paul<br>
<br>
<br>
----- Original Message -----<br>
From: <a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.gov</a><br>
To: <a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.gov</a><br>
</div><div><div>Sent: Saturday, October 12, 2013 11:17:06 AM<br>
Subject: Re: [Nek5000-users] Variable density flows<br>
<br>
<br>
<br>
Thanks to Paul and Ammar. I will try the variable density approach.<br>
<br>
<br>
I am first trying a case in which viscosity depends on temperature and a passive scalar. My uservp looks like this. Can I use "temp" and "PS" to get temperature and passive scalar as below ?<br>
<br>
<br>
<br>
subroutine uservp (ix,iy,iz,ieg)<br>
include 'SIZE'<br>
include 'TOTAL'<br>
include 'NEKUSE'<br>
common /mygeom/ xmin,xmax<br>
common /myparam/ r_k,Rey_no,Pr_no,Sc_no,visc_rat<br>
<br>
<br>
if(ifield.eq.1)then ! momentum equation<br>
utrans= 1.0<br>
udiff = exp(PS(1)*log(visc_rat) - temp)/Rey_no<br>
else if(ifield.eq.2)then ! temperature eqn<br>
utrans= 1.0<br>
udiff = PS(1)*(r_k - 1.0) + 1.0<br>
udiff = udiff/(Rey_no*Pr_no)<br>
else if(ifield.eq.3)then ! passive scalar<br>
utrans= 1.0<br>
udiff = 1.0/(Rey_no*Sc_no)<br>
else<br>
print*,'Only 3 fields'<br>
call exitt()<br>
endif<br>
<br>
<br>
return<br>
end<br>
<br>
<br>
Thanks<br>
praveen<br>
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