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

Simulation of cylinder aligned in the flow direction using k-e model

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 12, 2012, 14:06
Default Simulation of cylinder aligned in the flow direction using k-e model
  #1
New Member
 
Eli_Ja
Join Date: Jan 2011
Location: NJ
Posts: 7
Rep Power: 15
Eliasjal is on a distinguished road
Hello everyone,

First of all , i' still a beginner to fluent and what I'm trying to simulate is the boundary layer flow over a cylinder aligned in the flow direction. Please see the attached picture that shows the boundary conditions. I used a periodic boundary between the inlet and the outlet of the domain whereas the mass flow rate was taken. Then I assumed the wall has no slip and outflow pressure for the outer domain.

I need some help from you guys to resolve the following questions:

1- Is the BCs that i used are corrects ?? I wonder whether or not do i have to use the field pressure instead of outflow pressure condition ??
2- How to define the number of layers that will be used for a wall zone. I need to plot Y+ vs u+ so I need to define the wall sublayer that will be used for y+ analyses ??
3- Do you guys have and reference link, paper or materials that shows a similar simulation that i can use for comparing my results ?
4- In case of a spinning wall, do i need to use a dynamic mesh or just using the cell zone conditions ?? and if so then what is the proper choice, the frame motion or the mesh motion ???


thank you very much for your help
Regards,

EJ
Attached Images
File Type: jpg 221.jpg (92.0 KB, 25 views)
Eliasjal is offline   Reply With Quote

Old   June 13, 2012, 05:27
Default
  #2
Senior Member
 
Join Date: Mar 2009
Location: Indiana, US
Posts: 186
Rep Power: 17
delaneyluke is on a distinguished road
First of your external domain has to be way bigger if you want to capture the flow over your cylinder. Browse the net for external domain sizes for your type of problem.

To answer your qns
1. Use a velocity inlet and pressure outlet. For outer walls use the far field pressure BC
2. Use any Y+ calculator available to find out first layer height
3. Not at the moment
4. In case of a spinning wall, you can give the angular velocity to the wall, you don't need to do a dynamic mesh analysis

P.S You could work with a sector instead of the entire cylinder

Regards
Luke
delaneyluke is offline   Reply With Quote

Old   June 13, 2012, 09:00
Default
  #3
New Member
 
Eli_Ja
Join Date: Jan 2011
Location: NJ
Posts: 7
Rep Power: 15
Eliasjal is on a distinguished road
Hey Luke,

First of all thank you much for your response.

If there is any specific relation that define how much the size of the domain must be ?? or how large the external domain (i.e the outer cylinder diameter ) should be for my case ??

Actually I tried to avoid using a rectangular box just to eliminate some edge effect at the corners of the domain which happens in the rectangular box domain.

Just one more thing about your answer for q.1:
actually, I'm not simulating the entire model of the cylinder but just a sector of it and that is why I used a periodic boundary conditions.

looking forward to hearing from you.
Thanks

EJ
Eliasjal 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
Simulation of a single bubble with a VOF-method Suzzn CFX 21 January 29, 2018 01:58
Incorrect Drag and Drag Coefficient for flow over a cylinder ozzythewise Main CFD Forum 8 June 13, 2012 07:24
Flow over a cylinder Ari Guerrero CFX 6 September 30, 2005 04:47
Inviscid Drag at subsonic, subcritical Mach # Axel Rohde Main CFD Forum 1 November 19, 2001 13:19
Simulation of the Flow past a circular cylinder using STAR-CD M. S. GUEROUACHE Main CFD Forum 0 October 1, 1998 11:51


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