CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

iterations process for steady solver and time dependence for unsteady

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

Like Tree4Likes

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 7, 2018, 13:24
Default
  #21
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 5,687
Rep Power: 60
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by serguei View Post
when you say:"but you have to wait until the run gives a physically correlated solution", do you mean when numerical transient is over, and some my control value, as you say:" oscillates around a well defined averaged level"? As far, as I understand, it not necessarily should be integral value, like total kinetic energy, but, for example,velocity magnitude in some control point? Isn't?

Well I strongly advice the use of the integral of the kinetic energy into the whole domain. In a statistically steady state, you should have a balance between production and dissipation. Therefore, if the plot of the total kinetic energy in time shows that it oscillates around an average (constant in time) value, you can consider that the numerical transient is over.
FMDenaro is offline   Reply With Quote

Old   May 10, 2018, 10:05
Default
  #22
Member
 
Serguei
Join Date: Mar 2015
Posts: 33
Rep Power: 8
serguei is on a distinguished road
Quote:
Originally Posted by FMDenaro View Post
Well I strongly advice the use of the integral of the kinetic energy into the whole domain. In a statistically steady state, you should have a balance between production and dissipation. Therefore, if the plot of the total kinetic energy in time shows that it oscillates around an average (constant in time) value, you can consider that the numerical transient is over.
I have the region, which I keep with constant temperature, what is equivalent to external energy supply. Thus, the check of total kinetic energy balance is not so straight forward.
serguei is offline   Reply With Quote

Old   May 10, 2018, 10:58
Default
  #23
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 5,687
Rep Power: 60
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by serguei View Post
I have the region, which I keep with constant temperature, what is equivalent to external energy supply. Thus, the check of total kinetic energy balance is not so straight forward.

Not sure about what you are doing but if you are prescribing a constant temperature that means you let the heat flux to asses from the solution. Therefore you can have part of the region having heat entering into the domain and part leaving, insn't that?
FMDenaro is offline   Reply With Quote

Reply

Tags
iterations, steady, unsteady

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
Segmentation fault when using reactingFOAM for Fluids Tommy Floessner OpenFOAM Running, Solving & CFD 4 April 22, 2018 12:30
Floating point exception error lpz_michele OpenFOAM Running, Solving & CFD 53 October 19, 2015 02:50
Star cd es-ice solver error ernarasimman STAR-CD 2 September 12, 2014 00:01
Moving mesh Niklas Wikstrom (Wikstrom) OpenFOAM Running, Solving & CFD 122 June 15, 2014 06:20
pimpleFoam: turbulence->correct(); is not executed when using residualControl hfs OpenFOAM Running, Solving & CFD 3 October 29, 2013 08:35


All times are GMT -4. The time now is 15:40.