[snappyHexMesh] Calculating Y+ & understanding the Snappyhexmesh log file

Doug68 · March 14, 2016, 20:51

I'm trying to work out the Y+ values I'm getting from created meshes.
Looking at the log file I see:

patch faces layers overall thickness
...................[m].....[%]
----- ----- ------ --- ---
Wing 1936859 0.883 0.000926 79.4

I'm guessing the 0.000926m value is the final layer thickness?
What does the 79.4% mean?

Are the contents of the log file documented somewhere?
I've been unable to find it, if it is a link in that direction would be great.

Thansks.

mqsim · April 26, 2016, 08:31

Hi Doug68,

Did you find an answer to your issue?

Doug68 · April 26, 2016, 20:17

No I did not find a decent answer, frankly I think the documentation of OF is not that good there's a few things I've just come to a dead end on trying to work out.

As for Y+ there's a post processing function "yPlus" that'll create data you can use in paraFoam. I'm not sure if this is actually creating Y+ or Y*.
Looking at the data and doing the math by hand to calculate Y+ some of the figures it presents look suspiciously small, so I'm not that confident in that either.

mqsim · April 27, 2016, 04:41

I have not seen a better way than doing the math by hand for Y+ for the moment... At least we will be sure of what we have and no need to dig into OF documentation

March 14, 2016, 20:51	Calculating Y+ & understanding the Snappyhexmesh log file	#1
Doug68 Member Join Date: Nov 2010 Posts: 62 Rep Power: 15	I'm trying to work out the Y+ values I'm getting from created meshes. Looking at the log file I see: patch faces layers overall thickness ...................[m].....[%] ----- ----- ------ --- --- Wing 1936859 0.883 0.000926 79.4 I'm guessing the 0.000926m value is the final layer thickness? What does the 79.4% mean? Are the contents of the log file documented somewhere? I've been unable to find it, if it is a link in that direction would be great. Thansks.

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April 26, 2016, 08:31		#2
mqsim New Member Join Date: Feb 2016 Posts: 28 Rep Power: 10	Hi Doug68, Did you find an answer to your issue?

April 26, 2016, 20:17		#3
Doug68 Member Join Date: Nov 2010 Posts: 62 Rep Power: 15	No I did not find a decent answer, frankly I think the documentation of OF is not that good there's a few things I've just come to a dead end on trying to work out. As for Y+ there's a post processing function "yPlus" that'll create data you can use in paraFoam. I'm not sure if this is actually creating Y+ or Y*. Looking at the data and doing the math by hand to calculate Y+ some of the figures it presents look suspiciously small, so I'm not that confident in that either.

April 27, 2016, 04:41		#4
mqsim New Member Join Date: Feb 2016 Posts: 28 Rep Power: 10	I have not seen a better way than doing the math by hand for Y+ for the moment... At least we will be sure of what we have and no need to dig into OF documentation