[Nek5000-users] Problem when running with variable fluid properties

[nek5000-users at lists.mcs.anl.gov]

Hi,

After successfully running some DNS cases of a turbulent pipe with heat
transfer in NEK (
http://www.sciencedirect.com/science/article/pii/S0142727X15000533), I am
now struggling to run a similar case but with variable fluid properties (Re
and Pe being functions of temperature).

I am currently using Pn-Pn2 (lx2=lx1-2 in SIZE) method and stress
formulation (IFSTRS=true), together with IFUSERVP=true (p030=1.0 in REA
file) to be able to define the viscosity and conductivity functions.
Initial flow conditions are taken from a previous constant fluid properties
turbulent pipe case.

My problem is that, when setting IFUSERVP=true, the flow velocities go to
zero in very few time steps, even though I was setting constant fluid
properties in USERVP subroutine for trial purposes.

I have checked that the forcing in the momentum equation (subroutine USERF)
is correctly set.

Could you please give me some indications as to what I can be doing wrong?
Thanks in advance.

Regards
Antonio



-- 
ANTONIO ANTORANZ PERALES
Universidad Carlos III de Madrid
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