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

Time periodic heating

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 3, 2012, 05:11
Default Time periodic heating
  #1
New Member
 
Join Date: Aug 2012
Posts: 2
Rep Power: 0
mfuchs is on a distinguished road
Hi,

Im trying to modell the following 2d-system. There is a glas plate with a thickness of about 2mm and about 4 cm length. It is covered with a thin metall film (~ 10 microns). The film is periodocally heated from the upper side on one end of the system by a given heat current with an frequency of about 100 mHz. The heat sink is placed on the opposite end of the glas plate and is just a wall with constant temperature (293K)



The modelling and meshing is fine but it turns out that it takes very long to calculate and evaluate the experiment. The problem is that I have to use rather small timesteps (1/1000 sec) because of the evaluation that follows after the simulation. So here is the question:

Is it possible to get a time periodic solution? I have found something similar for ansys fluent:

https://www.sharcnet.ca/Software/Flu...ug/node392.htm

I do not need the start up phase but the start up phase lasts some hundred seconds. When I load the results in Ansys post it takes hours to get graphs.

thanks for your help
mfuchs
mfuchs is offline   Reply With Quote

Old   September 5, 2012, 10:13
Default
  #2
New Member
 
Sascha
Join Date: May 2012
Location: Germany
Posts: 8
Rep Power: 5
SaschaGH is on a distinguished road
Hey mfuchs,

if I understand you correctly all you need to do is manually delete the unnecessary (.trn) of the start up process (check with your timestepsize) or a priori define in cfx-pre when the output of your transient results should begin, which can be done in the output control tab. With the reduced number of timesteps you can then create a transient chart in post to see whether your problem has time periodic character.

If your startup phase lasts some "hundred" seconds but you use 1/1000 sec, how many hours/days does it take to calculate the problem ? Ever thought of using a bigger timestep for the beginning to obtain transient stabilization faster and then switch to the desired timestep for evaluation ?
Greetings
SaschaGH is offline   Reply With Quote

Old   September 11, 2012, 05:00
Default
  #3
New Member
 
Join Date: Aug 2012
Posts: 2
Rep Power: 0
mfuchs is on a distinguished road
ok this works fine. Thank you.
mfuchs 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
SLTS+rhoPisoFoam: what is rDeltaT??? nileshjrane OpenFOAM Running, Solving & CFD 4 February 25, 2013 05:13
plot over time fferroni OpenFOAM Post-Processing 7 June 8, 2012 07:56
Multiple floating objects CKH OpenFOAM 10 September 21, 2011 23:13
Residence Time Distribution with Periodic Boundary Conditions sanjose FLUENT 0 October 18, 2010 10:11
Plot heating and cooling rate (dT/dt) vs time Frederic FLUENT 0 February 6, 2005 05:00


All times are GMT -4. The time now is 04:45.