CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

Abnormal (?) Passive Scalar behaviour

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 26, 2014, 23:21
Default Abnormal (?) Passive Scalar behaviour
  #1
cwl
Senior Member
 
Chaotic Water
Join Date: Jul 2012
Location: Elgrin Fau
Posts: 433
Rep Power: 17
cwl is on a distinguished road
Simple case:
Rectangular axisymmetric 2D Porous Region 1.0x0.25m:
Inlet (short edge; any kind of boundary condition - just for velocity about 1 m/s),
Outlet (short edge; Pressure Outlet),
Wall,
Axis;

Ideal Gas;
Implicit Unsteady;
Coupled Energy;
Passive Scalar with "No Convection or Diffusion";
Region->Passive Scalar Source->Checked;
Passive Scalar Source = 0.0;

Initial: Temperature = 20 C, Passive Scalar = 20
Inlet: Temperature = 1800 C, Passive Scalar = 20 or 1800
Outlet: Temperature = 20 C, Passive Scalar = 20

Time Step = 0.025 s;

The problem is that though Passive Scalar should be constant across the Region - its value increases just with the Temperature if Passive Scalar Source is switched on (though it is set to zero) and does not if Passive Scalar Source is switched off.

I would be grateful for any suggestions or ideas - is it i am mistaken or it is a kind of program error.
cwl is offline   Reply With Quote

Old   October 3, 2014, 09:05
Default
  #2
cwl
Senior Member
 
Chaotic Water
Join Date: Jul 2012
Location: Elgrin Fau
Posts: 433
Rep Power: 17
cwl is on a distinguished road
I am sorry to up the topic - but i still hope someone may clear the things out for me.

The problem remains the same:
Passive Scalar with No Convection/Diffusion and with Passive Scalar Source checked but value set to 0 - is affected by the flow, while it should not as it its equation is just dϕ/dt = 0, where d - is partial derivative. This happens regardless of Time Step, Maximum Inner Iterations, CFL - and regardless of Residuals.
cwl is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
whats the cause of error? immortality OpenFOAM Running, Solving & CFD 13 March 24, 2021 08:15
Diverging solution in transonicMRFDyMFoam tsalter OpenFOAM Running, Solving & CFD 30 July 7, 2014 07:20
compressible flow in turbocharger riesotto OpenFOAM 50 May 26, 2014 02:47
is internalField(U) equivalent to zeroGradient? immortality OpenFOAM Running, Solving & CFD 7 March 29, 2013 02:27
passive scalar for carbon monoxide kraizy STAR-CCM+ 0 October 12, 2009 21:13


All times are GMT -4. The time now is 04:22.