CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum

Simulated air velocity near ceiling

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

LinkBack Thread Tools Display Modes
Old   July 1, 1999, 04:13
Default Simulated air velocity near ceiling
Apple L S Chan
Posts: n/a
Dear all

I am running a CFD simulation for air coming out from a wall diffuser near the ceiling of a room. The simulated velocity near the ceiling is much greater than that from measuered value. That means viscous friction exerted by the ceiling had not been well modelled. In my CFD code, logarithmic law is used. Could any one please advice me how to get better simulated velocity near the ceiling?

Thanks a lot!

Apple Chan
  Reply With Quote

Old   July 1, 1999, 21:13
Default Re: Simulated air velocity near ceiling
John C. Chien
Posts: n/a
(1). Was the initial flow field simulated properly? The air must be routed through a duct behind the outlet ( the diffuser). After going through the diffuser ( the outlet), there is a velocity distribution in three directions. (2). So, if the boundary condition is set at the diffuser exit, then the velocity distribution vx, vy, and vz must match the actual distribution first. (3). Even if there is only a thin slot at the diffuser exit, you still need to use the actual velocity distribution as the initial condition. (3). Then you need to have enough number of mesh points to cover the diffuser exit and the development of the wall jet (jet next to the ceiling wall).
  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
air bubble is disappear increasing time using vof xujjun CFX 9 June 9, 2009 07:59
the air velocity is not zero on the wall? Li Rong CFX 4 June 13, 2007 12:09
Velocity in Porous medium : HELP! HELP! HELP! Kali Sanjay Phoenics 0 November 6, 2006 07:10
Comet - air velocity Tony Campbell Siemens 3 November 10, 2004 03:37
HELP!!! Indoor air flow pattern Peter Zhang Main CFD Forum 4 November 3, 1999 03:49

All times are GMT -4. The time now is 10:47.