CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

Y+ value for logarithmic region

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

LinkBack Thread Tools Search this Thread Display Modes
Old   January 15, 2020, 17:44
Default Y+ value for logarithmic region
New Member
Join Date: Nov 2018
Posts: 4
Rep Power: 3
Muhammad Asim Sarwar is on a distinguished road
Hi all. I am doing simple CFD simulation flow over spherical body to understand the concept of y+ and boundary layer.

I have a simple question related to log-law layer. I read that for this region y+ value should be between 30 to 300 range. Now, how I would know that for my current simulation y+ value 35 is better or 50 or something higher value?
Muhammad Asim Sarwar is offline   Reply With Quote

Old   January 15, 2020, 18:04
Senior Member
Lucky Tran
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 3,663
Rep Power: 45
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
First, y+ is a fancy coordinate system. Do not confuse this with the more popular wall y+, which specifically refers to the y+ of the cell centroid of the wall adjacent cell. This wall y+ is the y+ of the cell nearest the wall.

The log-layer is indeed the region where the y+ is roughly between 30 and a few hundred. For just about any wall-bounded flow with a boundary layer, you can find this log region no matter if the BL is only a few millimeters thick, a kilometers thick, or millions of kilometers thick.

So given any flowfield, you (in theory) should be able to calculate the y+ field. That means you have already solved your problem (i.e. run your simulation first). You can then go to the cells nearest the wall, and find the y+ of just those cells. Then you can inspect the value if it is 30, 50, 100, or whatever. y+ is determined a posteriori, not a priori.
LuckyTran is offline   Reply With Quote


boundary layer, cfd, log layer, y+ value

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
Problem simulating the temperature rise in a composite material (chtMultiRegionFoam) Adam_K OpenFOAM Running, Solving & CFD 2 March 27, 2019 07:51
[mesh manipulation] Importing Multiple Meshes thomasnwalshiii OpenFOAM Meshing & Mesh Conversion 18 December 19, 2015 19:57
[Commercial meshers] Using starToFoam clo OpenFOAM Meshing & Mesh Conversion 33 September 26, 2012 05:04
[Other] StarToFoam error Kart OpenFOAM Meshing & Mesh Conversion 1 February 4, 2010 05:38
[Gmsh] Import gmsh msh to Foam adorean OpenFOAM Meshing & Mesh Conversion 24 April 27, 2005 09:19

All times are GMT -4. The time now is 00:00.