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

Proper Wind Tunnel Inlet BC for Fans and Other Streamwise Flow Acceleration Devices

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 19, 2012, 00:45
Default Proper Wind Tunnel Inlet BC for Fans and Other Streamwise Flow Acceleration Devices
  #1
Senior Member
 
Robert
Join Date: Sep 2010
Posts: 139
Rep Power: 5
lordvon is on a distinguished road
Hello everyone,

I was wondering what would be the proper inlet boundary condition to mimic a wind tunnel in the case of a propeller or similar device in the test section that accelerates the flow in the streamwise direction.

If we simply use a fixed velocity inlet then unphysical results may occur, since in a real wind tunnel the fixed velocity inlet would not be enforced so rigidly.

Would a total pressure condition be sufficient?
lordvon is offline   Reply With Quote

Old   June 19, 2012, 01:42
Default
  #2
Senior Member
 
Joern Beilke
Join Date: Mar 2009
Location: Dresden
Posts: 170
Rep Power: 7
JBeilke is on a distinguished road
The "correct" way to deal with this is to simulate the wind tunnel before and take the flow values (velocity, turbulence, temperature) from the inletsection as input values.

Otherwise do a good measurement of the values.
JBeilke is offline   Reply With Quote

Old   June 19, 2012, 11:29
Default
  #3
Far
Super Moderator
 
Far's Avatar
 
Sijal Ahmed Memon (turboenginner@gmail.com)
Join Date: Mar 2009
Location: Islamabad Pakistan
Posts: 3,743
Blog Entries: 6
Rep Power: 36
Far will become famous soon enoughFar will become famous soon enough
Send a message via Skype™ to Far
You can find all details in this paper (I am one of the authors)

Masud, J., and Ahmed, S. "Design Refinement and Performance Analysis of Two-Stage Fan for Small Turbofan Engines", Paper # AIAA-2007-23, 45th AIAA Aerospace Sciences Meeting and Exhibit at Reno, Nevada, USA (2007)


http://pdf.aiaa.org/preview/CDReadyM.../PV2007_23.pdf
Far is offline   Reply With Quote

Old   June 27, 2012, 12:17
Default
  #4
Senior Member
 
Robert
Join Date: Sep 2010
Posts: 139
Rep Power: 5
lordvon is on a distinguished road
I think I will just go with the openfoam BC of totalPressure (atmospheric + dynamic pressures) for the inlet, and atmospheric pressure for the outlet.
lordvon is offline   Reply With Quote

Old   June 27, 2012, 12:54
Default
  #5
New Member
 
Andras
Join Date: Aug 2011
Posts: 1
Rep Power: 0
akiss20 is on a distinguished road
Quote:
Originally Posted by lordvon View Post
I think I will just go with the openfoam BC of totalPressure (atmospheric + dynamic pressures) for the inlet, and atmospheric pressure for the outlet.
Is your tunnel a closed system? If so, the pressure boundary condition for the outlet may not be valid.

My 2 cents
akiss20 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



All times are GMT -4. The time now is 16:50.