CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Post-Processing

rhoSimpleFoam yPlus

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

Like Tree2Likes
  • 2 Post By simrego

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 14, 2018, 17:32
Default rhoSimpleFoam yPlus
  #1
New Member
 
Thomas M
Join Date: Aug 2018
Posts: 20
Rep Power: 7
tmik is on a distinguished road
Hi all,


I just ran into something very strange to me. I'm solving a compressible flow using rhoSimpleFoam, and am confused as to how the yPlus function works.


It looks like the yPlus function gave me a calculation for each results set I have. Furthermore, looking at the values, they are different between iterations. There's no reason for y+ to be changing, right? I'm using a mesh I made in Salome, not moving or anything.



y+ is a geometric parameter, based on my mesh - so why does it change with each iteration?


Code:
...

Time = 1900
Reading thermophysical properties

Selecting thermodynamics package
{
    type            hePsiThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState perfectGas;
    specie          specie;
    energy          sensibleInternalEnergy;
}

Reading field U

Reading/calculating face flux field phi

pressureControl
    pMax 1.28091e+06
    pMin 64045.4

Creating turbulence model

Selecting turbulence model type RAS
Selecting RAS turbulence model kOmegaSST
RAS
{
    RASModel        kOmegaSST;
    turbulence      on;
    printCoeffs     on;
    alphaK1         0.85;
    alphaK2         1;
    alphaOmega1     0.5;
    alphaOmega2     0.856;
    gamma1          0.555556;
    gamma2          0.44;
    beta1           0.075;
    beta2           0.0828;
    betaStar        0.09;
    a1              0.31;
    b1              1;
    c1              10;
    F3              false;
    decayControl    false;
    kInf            0;
    omegaInf        0;
}

No MRF models present

yPlus yPlus write:
    writing field yPlus
    patch walls y+ : min = 14.6179, max = 1200.02, average = 452.317

Time = 2000
Reading thermophysical properties

Selecting thermodynamics package
{
    type            hePsiThermo;
    mixture         pureMixture;
    transport       const;
    thermo          hConst;
    equationOfState perfectGas;
    specie          specie;
    energy          sensibleInternalEnergy;
}

Reading field U

Reading/calculating face flux field phi

pressureControl
    pMax 1.28091e+06
    pMin 64045.4

Creating turbulence model

Selecting turbulence model type RAS
Selecting RAS turbulence model kOmegaSST
RAS
{
    RASModel        kOmegaSST;
    turbulence      on;
    printCoeffs     on;
    alphaK1         0.85;
    alphaK2         1;
    alphaOmega1     0.5;
    alphaOmega2     0.856;
    gamma1          0.555556;
    gamma2          0.44;
    beta1           0.075;
    beta2           0.0828;
    betaStar        0.09;
    a1              0.31;
    b1              1;
    c1              10;
    F3              false;
    decayControl    false;
    kInf            0;
    omegaInf        0;
}

No MRF models present

yPlus yPlus write:
    writing field yPlus
    patch walls y+ : min = 4.23512, max = 906.382, average = 453.212

End
tmik is offline   Reply With Quote

Old   September 16, 2018, 16:53
Default
  #2
Senior Member
 
anonymous
Join Date: Jan 2016
Posts: 416
Rep Power: 14
simrego is on a distinguished road
Hi!


Yes, it is calculated for every timestep since yPlus is NOT a fully geometric parameter. Check this:
https://www.cfd-online.com/Wiki/Dime...tance_(y_plus)
yPlus is also depending on the friction velocity.
If you are running a steady state calculation, you can call the utility with the switch "-latestTime", so it will calculate the yPlus value only in the last timestep.
y_jiang and tmik like this.
simrego 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
[Other] Contribution a new utility: refine wall layer mesh based on yPlus field lakeat OpenFOAM Community Contributions 58 December 23, 2021 03:36
yPlus twoPhaseEulerFoam Andrea_85 OpenFOAM Post-Processing 4 January 11, 2021 06:01
OF 4.0 multiregion case calculate yPlus pbnuclex OpenFOAM Post-Processing 6 July 16, 2020 05:27
yplus value openfoam turbulent analysis massakimi Main CFD Forum 20 January 6, 2018 17:08
heat transfer coefficients with "bad" yplus Andrew Main CFD Forum 4 April 8, 1999 05:43


All times are GMT -4. The time now is 00:04.