CFD Online Logo CFD Online URL
Home > Forums > STAR-CCM+

Zero gradient pressure @ pressure outlet Boundary

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

Like Tree2Likes
  • 1 Post By rabat
  • 1 Post By vivekcfd

LinkBack Thread Tools Display Modes
Old   March 23, 2009, 08:55
Default Zero gradient pressure @ pressure outlet Boundary
New Member
Join Date: Mar 2009
Location: Belgium
Posts: 13
Rep Power: 10
rabat is on a distinguished road

I got a back flow in pressure outlet boundary.
To avoid the back flow in starccm+, we can change the boundary condition with the user-code, somethings like zero gradient pressure @ outlet.
Did anyone programme the zerogradP in c or fortran?
How can I solve this probleme?

Thanks in Advance,

ehsan-rezvanian likes this.
rabat is offline   Reply With Quote

Old   November 17, 2014, 09:30
Default hi
Qureshi M Z I
Join Date: Sep 2013
Posts: 75
Rep Power: 6
m zahid is on a distinguished road
have u find the answer, about setting "zero pressure gradient boundary condition" ? i want to set the zero pressure gradient at outlet, could u please share with me your experience, how can i set this ?

m zahid is offline   Reply With Quote

Old   January 21, 2015, 19:31
Question Zero-Gradient boundary condition Star CCM+???
New Member
Join Date: Oct 2010
Posts: 2
Rep Power: 0
FluidsExpert is on a distinguished road
Did you happen to find a solution. I also wish to define a zero-gradient boundary condition in Star CCM+.

FluidsExpert is offline   Reply With Quote

Old   January 28, 2015, 08:50
Vivek Kumar
Join Date: Mar 2009
Location: Switzerland
Posts: 35
Blog Entries: 1
Rep Power: 10
vivekcfd is on a distinguished road
It is quite straight forward to implement this boundary condition in starccm+.

1) You create new field function e.g. called PresCC (Pressure at cell centers) and assign variable $Pressure to it. Very important=>=> Do not forget to select option "Ignore Boundary Values". This way your new variable PresCC at the boundaries has the values of pressure next to the boundary.
2) Now go to the outlet boundary and select Field Function option and select PresCC as the pressure at the outlet boundary.

In this way you will set pressure at boundary equal to the pressure at the center of the boundary control-volume. This is what a zero-gradient boundary means.

But I still suggest to first try to extend your outlet in order to avoid with the back flow before trying zero-gradient boundary for the pressure.
ehsan-rezvanian likes this.
vivekcfd is offline   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
Pressure boundary condition C-H Kuo Main CFD Forum 18 September 16, 2016 03:19
simple model, difficult outlet Eric CFX 7 May 23, 2014 08:13
pressure outlet boundary condition Sastry FLUENT 4 February 19, 2011 02:33
Setting Pressure on an Outlet Boundary Richard Pemberton CFX 2 April 12, 2001 06:35
Hydrostatic pressure in 2-phase flow modeling (long) DS & HB Main CFD Forum 0 January 8, 2000 16:00

All times are GMT -4. The time now is 21:40.