[lakeat]

Dear all,


As discussed in this thread, there is a need to refine the wall layer mesh based on the yPlus or yStar information on the patch fields.

So I modified the original refineWallLayer utility and make a "smart"-refine-wall-layer-mesh utility.

Here it is: refineWallLayerSmart.tar.gz

Most of the options are similar to the original refineWallLayer utility, only
"esgeWeight" is replaced by "stretchingRatio", which I think will make more sense. It should be larger than 1, best to be around 1~1.5, in order not to have too big stretching ratios.

The key feature here is to refine the mesh not just once, but many times based on the current yPlus file or yStar file information, so to reach a desired estimated yPlus value.

The default yPlus target value is to reach y+=1;
Of cause you can set any other y+ target;

To use this utility, please turn on the "basedOnYPlus" option.

If "basedOnYPlus" option is off, the utility behaves like original refineWallLayer utily.

I do not see a need to use "cellSet" mechanism, so by default, when the "basedOnYPlus" option is turned on, the whole wall layer is refined.

Of cause however, this method is just a rough estimation, the real flow field and the yPlus values need to you to rerun the simulation!

$ refineWallLayerSmart -help

Usage: refineWallLayerSmart [OPTIONS] <patchName> <stretchingRatio>
options:
  -basedOnYPlus     Based on y+/y* field, run these utilities first. Target
                    yPlus is unity
  -case <dir>       specify alternate case directory, default is the cwd
  -noFunctionObjects
                    do not execute functionObjects
  -overwrite        overwrite existing mesh/results files
  -refineLevel <value>
                    Manually set the refineLevel, e.g. 3
  -targetYPlus <value>
                    Manually set the target yPlus, e.g. 5 or 30
  -useSet <name>    (obsoleted) restrict cells to refine based on specified
                    cellSet name
  -srcDoc           display source code in browser
  -doc              display application documentation in browser
  -help             print the usage

A smart way to refine wall layer cells based on the y+/y* value.
Please turn on the option "basedOnYPlus"to see its effect

Examples:

refineWallLayerSmart -basedOnYPlus cyl 1.15

Refine the wall patch cells named "cyl" based on the latestTime yPlus information, the refine level is automatically calculated, in order to reach y+=1.

refineWallLayerSmart -basedOnYPlus -targetYPlus 30 cyl 1.15

refine the wall layer mesh to have a target yPlus 30 (mean yPlus value is compared in the utility.)
If "-targetYPlus 50" is larger than the mean yPlus value on that patch, error will show. That is no need to refine.

refineWallLayerSmart -basedOnYPlus -targetYPlus 30 -refineLevel 3 cyl 1.15

Same as above, but refineLevel is forced to be three, so here "-targetYPlus 50" is useless.


The following is a sample output:

$ refineWallLayerSmart -basedOnYPlus -targetYPlus 2 cyl 1.12
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 2.1.0-5141eb679a6c
Exec   : refineWallLayerSmart -basedOnYPlus -targetYPlus 2 cyl 1.12
Date   : Nov 28 2012
Time   : 18:29:59
Host   : "ubuntuWorkStation"
PID    : 13010
Case   : .../run/test/rectangular
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0.01

Note: this utility default is using yPlus, if you have yStar file also in the folder, 
      please double check which one you want to use, and delete the other. Thanks!

Using refineWallLayer utility in a smart way!

Mean yPlus is 19.8019, targetYPlusValue is 2, refineLevel is 4

        Originally, patch 0 named cyl
         d  : min: 0.00069375 max: 0.0008625 average: 0.000735

Selected 284 cells connected to patch cyl

Cutting:
    cells:284
    edges:568

Morphing ...
Selected 284 cells connected to patch cyl

Cutting:
    cells:284
    edges:568

Morphing ...
Selected 284 cells connected to patch cyl

Cutting:
    cells:284
    edges:568

Morphing ...
Selected 284 cells connected to patch cyl

Cutting:
    cells:284
    edges:568

Morphing ...
Writing refined morphMesh to time 0.01001

        After refining, Patch 0 named cyl
         d  : min: 5.405e-05 max: 6.7e-05 average: 5.72429e-05

End

Comments and suggestions are very welcome!
Cheers,