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

stationary flow - transient temperature

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 2, 2003, 09:00
Default stationary flow - transient temperature
  #1
Nicola
Guest
 
Posts: n/a
Hey all,

I have a complex geometry with two separated fluids with constant velocities and

1.) the same temperature which differs from the solid temperature. I want to calculate the heating up of the solid

2.) one fliud with constant temperature and the other with a varying temperature ramp. I also want to calculate the heating up of the solid

As I get a maximum time step of 0.02 s for my flow condition it is quite uncomfortable to calculate fully transient. Is there a possibility to treat the flow as stationary and only the conjugate heat transfer as transient? How can I do the set-up for this calculation?

Regards,

Nicola
  Reply With Quote

Old   June 2, 2003, 12:04
Default Re: stationary flow - transient temperature
  #2
Joern Beilke
Guest
 
Posts: n/a
If you are sure that the flow does not change anymore you can switch off the calculation of velocity, pressure ... and only solve for the temperature with a much larger time step.

Later you can switch on the flow for some time steps ...
  Reply With Quote

Old   June 3, 2003, 09:39
Default Re: stationary flow - transient temperature
  #3
Nicola
Guest
 
Posts: n/a
Thanks a lot, it's running much faster. Is there an equation for the max time step for conjugate heat transfer equivalent to the equation for the transient piso? Do you know how the convective heat transfer is solved without solving the velocity? Is the existing velocity from the restart file used?

Regards,

Nicola
  Reply With Quote

Old   June 10, 2003, 11:11
Default Re: stationary flow - transient temperature
  #4
Joern Beilke
Guest
 
Posts: n/a
You dont need to stop the calculation every time. Just define some load steps and use different settings for the solve command and the time step size.
  Reply With Quote

Old   June 16, 2003, 06:04
Default Re: stationary flow - transient temperature
  #5
Nicola
Guest
 
Posts: n/a
I tried to switch on the flow and pressure calculation for some time steps, with the transient file, in which only the energy equation is solved, as restart file. But it didn't work. Prostar accepts the switch, but in the calculation, it is not solved for neither velocities nor pressure...

Havew I to change anything in the previous set-up, or in the .prob file, or somewhere else?

Thanks for help,

Nicola
  Reply With Quote

Old   June 16, 2003, 06:44
Default Re: stationary flow - transient temperature
  #6
Joern Beilke
Guest
 
Posts: n/a
time trans
trfi init

! solve all for 10 time steps
solve,y,y,y,y,n,n,y,n,n,n,n,n,
lstep,1,10,cons,1e-5,N,0,0
lssave,1

! solve temperature for 100 steps
solve,n,n,n,n,n,n,y,n,n,n,n,n,
lstep,2,100,cons,1,N,0,0
lssave,2

! solve all for 10 time steps
solve,y,y,y,y,n,n,y,n,n,n,n,n,
lstep,2,10,cons,1e-5,N,0,0
lssave,2

lsra 1 3
...
  Reply With Quote

Reply


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
Air Flow around a stationary cylinder basilwatson OpenFOAM Running, Solving & CFD 1 May 26, 2008 07:37
Flow laminar and stationary of water in a pipe manuel OpenFOAM Running, Solving & CFD 6 March 24, 2007 19:23
Stationary Transient Peter CFX 1 June 27, 2006 18:50
Flow through circular curved stationary pipe R.Sripriya Main CFD Forum 0 May 13, 2005 07:07
applications of stationary incompressible flow Ravi Main CFD Forum 0 May 7, 2003 10:43


All times are GMT -4. The time now is 07:01.