CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > ANSYS Meshing & Geometry

[GAMBIT] 2D turbulent flow in axisymmetric sudden expansion

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

Like Tree2Likes
  • 1 Post By -mAx-
  • 1 Post By -mAx-

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 22, 2014, 10:06
Default 2D turbulent flow in axisymmetric sudden expansion
  #1
New Member
 
cecè
Join Date: Dec 2014
Posts: 3
Rep Power: 9
Cesare88 is on a distinguished road
hi guys,

I am a student in mechanical engineering . I'm working on a project for the cfd examination and I can not find a solution to the problem .
in particular I have to study the 2D turbulent flow of water in a pipe with a sudden expansion using the wall function approach and the near wall modeling approach and compare the results . Could someone explain how to create the mesh in gambit to obtain a valid results from the simulation ??? in particular I would like to know how to get the correct value of y + for the two different approaches . If you have any links to be attached that explains this i am very grateful .

have a nice evening
Cesare88 is offline   Reply With Quote

Old   December 23, 2014, 02:06
Default
  #2
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,293
Rep Power: 39
-mAx- will become famous soon enough
For me: near wall modelling and wall function are linked
>>You will use a wall function for modelling effects near the walls

*y+ estimation --> http://www.cfd-online.com/Tools/yplus.php

*BL in Gambit --> https://www.sharcnet.ca/Software/Gam...tm#mesh_blayer
Cesare88 likes this.
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   December 23, 2014, 06:22
Default
  #3
New Member
 
cecè
Join Date: Dec 2014
Posts: 3
Rep Power: 9
Cesare88 is on a distinguished road
Hello max,

first of all thank you for responding to my question .
I do not know if I have to use to force the boundary layer or I can also use the MAP algorithm ?? I had divided the domain into four subdomains and using the map I made the mesh . I attach a photo of the mesh that I made so you can give me an opinion .
Thank You
have a nice day
Attached Images
File Type: jpg Cattura.jpg (66.3 KB, 19 views)
Cesare88 is offline   Reply With Quote

Old   December 23, 2014, 06:29
Default
  #4
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,293
Rep Power: 39
-mAx- will become famous soon enough
you can work with map, then your BL will be "integrated" within your mesh.
But if you want to adapt your BL, then it will give you some work.
If you create the BL, with the tool, then you will adapt it more easily

To convince you try to reduce your first cell's height with 50%
ghost82 likes this.
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   December 23, 2014, 06:47
Default
  #5
New Member
 
cecè
Join Date: Dec 2014
Posts: 3
Rep Power: 9
Cesare88 is on a distinguished road
well thanks for the advice ...
Now another question :
I have to create the BL only in the region after the sudden expansion or even in the inlet region ??
Looking at the photo of the mesh that I have attached you think it might be a good start for the study ????
If the kind of discretization is ok now I will create the BL where it is appropriate , and follow that road...
Cesare88 is offline   Reply With Quote

Old   December 23, 2014, 07:05
Default
  #6
Super Moderator
 
-mAx-'s Avatar
 
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,293
Rep Power: 39
-mAx- will become famous soon enough
create the BL on each wall (not at inlet or outlet)
__________________
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Issues on the simulation of high-speed compressible flow within turbomachinery dowlee OpenFOAM Running, Solving & CFD 11 August 6, 2021 07:40
Use of laminar model for a turbulent flow jcamilleri Main CFD Forum 1 July 6, 2014 07:54
Gas flow through a channel with sudden radius expansion Blooper SU2 4 June 5, 2014 16:40
UDF for fully developed turbulent flow at inlet soroushsaberi FLUENT 0 May 28, 2014 18:00
heat transfer in sudden expansion flow Adrian Yeap Main CFD Forum 1 October 27, 1998 11:15


All times are GMT -4. The time now is 02:33.