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

BCs in a Tunnel Modeling

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 15, 2011, 16:14
Default BCs in a Tunnel Modeling
  #1
New Member
 
Mehdi Famouri
Join Date: Jan 2011
Posts: 12
Rep Power: 6
mehdi8619 is on a distinguished road
Hi everyone,

I’m trying to study the velocity distribution next to the uppermost part of a car tunnel. The problem has been described below (I know this not a precise modeling, but all I need is a rough estimation). Here is the BCs I applied:



AA:

1- Moving wall (L=50 m, V=17.6 m/s)

2- Pressure-Inlet

3- Fixed wall

4- Pressure-Outlet


BB:

1- Moving wall (L=100 m, V=17.6 m/s)

2- Pressure-Inlet

3- Fixed wall

4- Pressure-Outlet


CC:

1- Moving wall (L=50 m, V=17.6 m/s)

2- Pressure-Inlet

3- Fixed wall

4- Outlet-vent


DD:

1- Moving wall (L=50 m, V=17.6 m/s)

2- Pressure-Inlet

3- Fixed wall

4- Outflow


The results are not similar, neither make sense! BTW, I solved both steady and unsteady. Also Turbulence (k-epsilon) modeling has been used. I’m not sure about 2 and 4 boundaries.

Does any one know what the best BCs are?




and here is the Computational Domain with the BCs:

Thanks in Advance,

Last edited by mehdi8619; February 15, 2011 at 18:57.
mehdi8619 is offline   Reply With Quote

Old   February 16, 2011, 18:54
Default
  #2
New Member
 
Join Date: Mar 2010
Posts: 18
Rep Power: 7
red_lemon is on a distinguished road
Correct boundary conditions are
1 - ground - moving wall at 17.6m/s
2 - outlet - pressure outlet 0Pa gauge
3 - roof - moving wall at 17.6m/s
4 - velocity inlet at 17.6m/s

assumes:
>you are modelling car in an actual tunnel and not wind tunnel which has fixed relative walls
>domain is large enough to allow turbulence profile to establish before impacting vehicle
>upper boundary is the actual roof and not domain cut off in which case it should be symmetry
>Note that wheels need MRF zones
>Ensure you use prisms on car if possible and have high density wake region captured behind

Hope that helps!
red_lemon 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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Dealing with BC's in OF 1.6 vkrastev OpenFOAM Running, Solving & CFD 5 September 4, 2012 11:58
free field modeling & BCs Serazio FLUENT 0 February 10, 2011 12:38
how to consider perforated wind tunnel wall in CFD simulation littlelz CFX 4 June 11, 2009 05:51
Wind tunnel modeling Pandu CFX 3 May 19, 2003 21:49
A conference in air load /flight simulation/flight test/wind tunnel test/aero modeling for high AOA cimsi Main CFD Forum 0 September 17, 1998 06:26


All times are GMT -4. The time now is 23:03.