[esp-r] Re: Time step control relaxation

[Pueltz, Gunter]

Dear Julio,
 
in addition to Achim´s mail following informations:
 
the default value of underelaxation is 0.25, which you can find in the
source file /esrumfs/mfmach.F.
But be aware that for activating underelaxation (for surpressing
oscillations) you must
de-comment the relaxation loop in the source-file mfmach.F first !!!
In the standard source code the relaxation-loop is NOT valid (commented
resp. deactivated) .....
Above the loop you will find a fortran line with the relax-factor of 0.25;
you can change this
value in the source code.
But also be aware of the variable ITRPAS, which does - in the current
version 11.2 (11.3 not yet investigated) -
NOT work correctly. The value of ITRPAS always remains at the integer value
of 0 and thus the if-condition
never is fulfilled. In version 11.2 you also have to change this source line
with the if-statement for activating underrelaxation ....
 
Good luck with underelaxation (which´is VERY important for surpressing
oscillations between thermal and air flow domain) !
 
regards,
Gunter

-----Original Message-----
From: esp-r-bounces at lists.strath.ac.uk
[mailto:esp-r-bounces at lists.strath.ac.uk]On Behalf Of giulio benincasa
Sent: Wednesday, April 18, 2007 11:57 AM
To: esp-r at lists.strath.ac.uk
Subject: [esp-r] Time step control relaxation


Dear all, 

I have read that is possible change relaxation parameter 

in source code to calm oscillations results  arrange to  (in the air-flow
network) similar temperature nodes and 

flow-connections that have very little pressure drops across them. 

There is anybody that know tje soutce code file where  make  modify  ??

Best regards 

Thank you in advance 

Giulio Benincasa




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