CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Error due to y+ value

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

LinkBack Thread Tools Display Modes
Old   November 7, 2006, 09:32
Default Error due to y+ value
Posts: n/a

I am simulating flow of air in pipe (long pipe with lots of elbow, bends etc) by FLUENT. I am using standard k-e turbulent model with standard wall function. My questions are:

1. Should I check wall y+ or y* value?

2. Lets say the y+ value is in the limit 15-200. But according to the theory we know lower limit is 30. With this current simulation (i mean value 15) what kind of error (%) will be introduced to the pressure drop data? Will it be considerable or negligible?

3. Its a huge model (around 3 million cell) and I am afraid I cant refine the mesh anymore. What do you recommend from your experience?

Thank you guys. Munni

  Reply With Quote

Old   November 8, 2006, 05:19
Default Re: Error due to y+ value
Ralf Schmidt
Posts: n/a

1. YES! y+ is extreamly importand, if you want to report drag - wall sher stress is calculated using the wall low - and that dependes on the wall function!

2. I am not so sure about that...

3. Use boundary layer option. that will give you a small wall disdance, but enables one to have the next cell larger. That reduces the number of cells.

  Reply With Quote


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 04:54.