CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

Instantaneous point release / advection-diffusion

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 20, 2013, 15:11
Default Instantaneous point release / advection-diffusion
  #1
New Member
 
April
Join Date: Jul 2011
Location: Ann Arbor, MI
Posts: 7
Rep Power: 7
april0100 is on a distinguished road
Hi All,

I am simulating what should be a very simple problem: laminar flow in a 2-d channel with scalar transport. I've amended icoFoam to include the scalar transport equation:

Code:
 fvScalarMatrix TEqn
    (
        fvm::ddt(T)
      + fvm::div(phi, T)
      - fvm::laplacian(DT, T) == f 
    );
where 'f' is a matrix that contains 0 everywhere at all times except at the time and location of the instantaneous release.

My problem is that the scalar 'T' is not properly being advected from the domain. That is, after some time the concentration of my scalar levels off and does not decrease further as shown in the attached plot.


I am thinking I may have a boundary condition problem. Currently I'm using zeroGradient boundaries on all sides of the channel for T. The inlet velocity is parabolic with a maximum centerline value of 2 m/s. If anyone has any ideas where I might be erring I would greatly appreciate it. Thanks,

April
Attached Images
File Type: jpg Toutlet.jpg (71.4 KB, 7 views)
april0100 is offline   Reply With Quote

Old   March 30, 2013, 12:59
Default
  #2
New Member
 
April
Join Date: Jul 2011
Location: Ann Arbor, MI
Posts: 7
Rep Power: 7
april0100 is on a distinguished road
In case anyone else has this problem, the solution is to set the inlet boundary condition to a fixed value of 0.
april0100 is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Extend Project Release 1.6-ext hjasak OpenFOAM Announcements from Other Sources 33 July 14, 2011 18:54
CFX Post: Problems with moving point cloud for changing time steps spatialtime CFX 0 December 7, 2009 05:56
BlockMeshmergePatchPairs hjasak OpenFOAM Native Meshers: blockMesh 11 August 15, 2008 07:36
Gmsh and samplesurface touf Open Source Meshers: Gmsh, Netgen, CGNS, ... 2 December 10, 2007 03:27
CFX4.3 -build analysis form Chie Min CFX 5 July 12, 2001 23:19


All times are GMT -4. The time now is 11:45.