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

What does it mean....????

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 30, 2001, 02:49
Default What does it mean....????
  #1
Sharad Dugad
Guest
 
Posts: n/a
Dear FLUENT USERS,

Wish you all a VERY HAPPY & PROSPOROUS NEW YEAR!!!

I am trying to model the upward seepage(also known as influent seepage or Injection) through the porous bed of an open channel.

For this I created necessary geometry in GAMBIT and called the bed of channel as "bott-face" and set it as "Porous Jump" boundry condition, and exported the mesh to FLUENT-5.

But while reading the .msh file in FLUENT-5, the following error message appears ....

"Can not change "bott-face" to "Porous Jump" because there is only one adjacent cell thread"

What does this mean? How to set the "Porous Jump" B.C. in Gambit?

If Anybody Knows it, Please Help.... Thanks.

SHARAD DUGAD
  Reply With Quote

Old   January 2, 2002, 02:55
Default Re: What does it mean....????
  #2
Jin-Wook LEE
Guest
 
Posts: n/a
I guess that your 'porous jump' is located at the boundary. Porous jump shoud not be located at the boundary.

Sincerely, Jinwook.
  Reply With Quote

Old   January 2, 2002, 04:06
Default Re: What does it mean....????
  #3
Sharad Dugad
Guest
 
Posts: n/a
Dear Jeanwook,

Thanx for the reply.

Consider that flow depth in channel is 25 cm & the underlying sand bed has a thickness of 10cm. Where should the porous jump be located? Pl. reply.

Sincerely,

Sharad Dugad.
  Reply With Quote

Old   January 2, 2002, 05:41
Default Re: What does it mean....????
  #4
Jin-Wook LEE
Guest
 
Posts: n/a
'underlying sand bed has a thickness of 10cm'. --> Then set the region of sand bed as porous media. For 3D analysis, porous media is for the volume and porous jump is for the surface.

Sincerely, Jinwook

  Reply With Quote

Old   January 2, 2002, 07:26
Default Re: What does it mean....????
  #5
Sharad Dugad
Guest
 
Posts: n/a
Dear Jeenwook,

If go for 3D flow, what boundary condition should I set at the interface of water and sand bed?

I know the seepage velocity at the interface of water and sand bed which is very low(0.0004m/s). With this velocity water enters the main channel flow which is turbulent. The problem is how to simulate the roughness of sand bed and upward velocity with a Single Boundary condition.

If I set "velocity inlet" B.C. for this bed, roughness effect is not taken into account & if I set it as "wall" BC, then I can not set the velocity. Also from which zone FLUENT should be made to solve for the solution in the "Initialize" panel?

Please Help.

Regards, Sharad
  Reply With Quote

Old   January 2, 2002, 20:24
Default Re: What does it mean....????
  #6
Jin-Wook LEE
Guest
 
Posts: n/a
CFD can do something not everything. But fortunately, if you set the sand region as 'POROUS ZONE', the overall effect can roughly be included in the 'porous region'.

Sincerely, Jinwook
  Reply With Quote

Old   January 5, 2002, 13:41
Default Re: What does it mean....????
  #7
Carlos
Guest
 
Posts: n/a
I hope your simulation is not transient or reacting.

If it is, it will be WRONG. Fluent does not take into account the porosity in the transport equations.
  Reply With Quote

Old   January 6, 2002, 14:16
Default Re: What does it mean....????
  #8
Sharad Dugad
Guest
 
Posts: n/a
Hi Carlos,

Please explain in detail what you wanted to state. Thanks!

Sharad..
  Reply With Quote

Old   January 15, 2002, 02:52
Default Re: What does it mean....????
  #9
Sharad Dugad
Guest
 
Posts: n/a
Dear Jeenwook,

Could you please reply each questions one by one basis. I am not getting response from other users hence troubling you.

PLEASE ANSWER THE FOLLOWING...

Q1.If I go for 3D flow, what boundary condition should I set at the interface of water and sand bed?

I know the seepage velocity at the interface of water and sand bed which is very low(0.0004m/s). With this velocity water enters the main channel flow which is turbulent. The problem is how to simulate the roughness of sand bed and upward velocity with a Single Boundary condition.

If I set "velocity inlet" B.C. for this bed, roughness effect is not taken into account & if I set it as "wall" BC, then I can not set the velocity.

Q2.From which zone FLUENT should be made to solve for the solution in the "Initialize" panel?

Please Help.

Regards, Sharad

  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 05:59.