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

Volume conservation / divergence errors

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 29, 2017, 16:15
Default Volume conservation / divergence errors
  #1
Senior Member
 
Join Date: Jul 2013
Posts: 124
Rep Power: 12
wildfire230 is on a distinguished road
Hi all,

I am running into a problem which I do not quite understand related to how exactly continuity errors are calculated. I am using the icoFoam solver. When I run the solver, I consistently have time step continuity errors that are on the order of 1e-16, and if I also have the code print max(fvc::div(phi)), this consistently gives values on the order of 1e-9 or less, except the first few time steps. However, when I view my results in paraview and calculate the divergence of the velocity field, it is 7-8 orders of magnitude larger. Also, when I have the code print max(fvc::div(U)), it is also 7-8 orders of magnitude larger than max(fvc::div(phi)).

I assume that this error is somehow introduced through an interpolation scheme somewhere along the way? However, it's very important for my results to have zero divergence in the velocity field.

I would greatly appreciate any help with this issue.

EDIT: I guess the question boils down to: why are fvc::div(U) and fvc::div(phi) different by 8 orders of magnitude???

Thanks.
wildfire230 is offline   Reply With Quote

Old   April 4, 2017, 13:45
Default
  #2
Senior Member
 
Join Date: Jul 2013
Posts: 124
Rep Power: 12
wildfire230 is on a distinguished road
Sorry for the bump, does anyone have any ideas on why fvc::div(U) and fvc::div(phi) could be different by 8 orders of magnitude?

Thanks.
wildfire230 is offline   Reply With Quote

Reply

Tags
continuity, divergence, volume conservation


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
how to set periodic boundary conditions Ganesh FLUENT 15 November 18, 2020 06:09
pimpleDyMFoam computation randomly stops babapeti OpenFOAM Running, Solving & CFD 5 January 24, 2018 05:28
How to use "translation" in solidBodyMotionFunction in OpenFOAM rupesh_w OpenFOAM Running, Solving & CFD 5 August 16, 2016 04:27
InterFoam negative alpha karasa03 OpenFOAM 7 December 12, 2013 03:41
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 11:55


All times are GMT -4. The time now is 08:12.