CFD Online Logo CFD Online URL
Home > Forums > FLUENT

why it doesn`t change

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

LinkBack Thread Tools Display Modes
Old   February 19, 2006, 05:26
Default why it doesn`t change
Posts: n/a
hi i trying to heat a tank filled with water. boudary condition: bottom wall temperature 500K, water temperature 300K, pressure of water 1013hPa. Iterations doing well, residuals too but after iterations density doesn`t change. Why. In real density of water change with temperature isn`t ? so why it doesn`t change in my model. Im using: unstady, VOF with body implict..., g=9.81m2/s. time step size 0,001s, number of time steps 100000 regards
  Reply With Quote

Old   February 21, 2006, 03:43
Default Re: why it doesn`t change
Posts: n/a
You have to explicitly include the density function of temperature the material data.....

Fluent will not change it if you use a fixed density!!
  Reply With Quote

Old   February 21, 2006, 06:58
Default Re: why it doesn`t change
Posts: n/a
Ok Thank you. I`ve already made an UDF and now everything seems to be ok. regards Grzesiek PS. Mabby you know what to do to have a specific heat changes with temperature changes. I`ve heard that "cp" is the only properties which can not be defined by UDF and must be constant. But what to do when it is a function of temperature and concentration ?
  Reply With Quote

Old   February 22, 2006, 02:59
Default Re: why it doesn`t change
Posts: n/a
Well you are right, it is strange that C_p cannot be modified with an UDF...

but you can use a piecewise-linear function of temperature...or polynomial function of temperature....I am sure you can find what you need
  Reply With Quote


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
How to change density in OpenFoam zhaowei OpenFOAM Running, Solving & CFD 7 December 11, 2014 09:36
Solid/liquid phase change fabian_roesler OpenFOAM 10 December 24, 2012 07:37
Change cell zone index/thread during simulation neilduffy1024 FLUENT 0 January 17, 2011 10:40
no enthalpy change across the momentum source Atit Koonsrisuk CFX 2 December 19, 2005 03:33
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12

All times are GMT -4. The time now is 22:36.