code_saturne User's Forum

Posted: **Tue Jun 11, 2013 5:39 am**

Hi
I am testing cs-3.0.1 for a heat transfer problem with buoyancy effect. As indicated in the user guide, icalhy = 1, if iphydr = 1 and gravity is different from zero, which is the case that I am testing. However, I do see the velocity oscillation and unphysical high velocity occur at the outlet boundary, which eventually leads to the divergence. Thus I try to set icalhy to be zero, but failed to find the suitable subroutine or any alternative. Can anybody kindly tell me where to go for the changes?
Thanks.

George XU
from Singapore

Posted: **Tue Jun 11, 2013 1:15 pm**

Hello,

In the GUI, check Numerical Parameters / Global Parameters / Improved pressure interpolation in stratified flow.

In cs_user_parameters.f90, iphydr is defined in subroutine usipgl, and icalhy may be set anywhere inside subroutine usipsu (even if no example is present).

Regards,

Yvan

Posted: **Wed Jun 12, 2013 9:42 am**

HI Yvan,
I have tried as per your instruction, but the solver failed to change the value for icalhy. It is still equal to 1, as shown in the log file.

regards,
George

Posted: **Wed Jun 12, 2013 1:26 pm**

Hello,

Looking at varpos.f90, the settings for icalhy are as follow:

Code: Select all

  if(iphydr.eq.0.or.iphydr.eq.2) then
    icalhy = 0
  elseif(iphydr.eq.1) then
    gravn2 = gx**2+gy**2+gz**2
    if (gravn2.lt.epzero**2) then
      icalhy = 0
    else
      icalhy = 1
    endif
  endif

So you need to make sure both iphydr = 1 and gravity is defined.

Is this the case in you setup ?

Regards,

Yvan

Posted: **Mon Jun 24, 2013 6:52 am**

Hi Yvan,
Yes, in my case, the gravity in the Z direction is set as -9.81. I guess that was the reason to fail to set icalhy = 0.

As defined in the code, the gravity needs to be disabled, which is not physically true for buoyancy-driven problem as I intend to simulate.

Appreciate your clarification on this.

regards,

George

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Re: how to change the value for parameter icalhy in cs-3.0.1

Re: how to change the value for parameter icalhy in cs-3.0.1