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September 4, 2006, 10:22
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Hello,
I was taking a look
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#1 |
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Member
Guido Adriaensen
Join Date: Mar 2009
Posts: 56
Rep Power: 17  |
Hello,
I was taking a look at the calculation of y-plus with the checkYPlus utility, but isn't this in fact a check for y-star? Y-star = rho*Cmu^0.25*sqrt(k)*y/mu y-plus = rho*sqrt(tau_w/rho_w)*y/mu Thus Y-star is related to the turbulent kinetic energy and y-plus to the wallshearstress, or am I now overlooking something? kind regards Guido |
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September 9, 2009, 15:49
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#2 |
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Member
Sven Schweikert
Join Date: Jun 2009
Posts: 38
Rep Power: 17 |
Hey Guido
I'm running some calculations with RSTMs and while checking y+ for the first cell I recognized the same. Checking via the yPlusRAS command creates totally different values than the calculation with: y+ = Utau*y/nu with Utau = SQRT(Tau_wall/rho) Meanwhile did you figured out something to avoid this curio? Thanks and regards, Sven |
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April 26, 2013, 11:03
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#3 |
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Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 27 |
although its old.but I have found that yPlusRAS uses y* furmula in return of y+.could anyone guide me or give an explanation on why?
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. |
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May 2, 2013, 12:40
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#4 | |
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Senior Member
Mojtaba Amiraslanpour
Join Date: Jun 2011
Location: Tampa, US
Posts: 308
Rep Power: 16  |
Quote:
Check out this post, Niklas has came up with a solution by modifying the file yPlusLES.C: http://www.cfd-online.com/Forums/ope...tml#post280296 best
__________________
Learn OpenFOAM in Persian SFO (StarCCM+ FLUENT OpenFOAM) Project Team Member Complex Heat & Flow Simulation Research Group If you can't explain it simply, you don't understand it well enough. "Richard Feynman" |
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May 2, 2013, 13:14
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#5 |
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Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 27 |
thanks Mojtaba.
but my case is compressible.do you know how to change the incompressible yPlus code? and also it doesn't compile in OF 2.2.0: Code:
ehsan@Ehsan-com:~/Desktop/yPlus$ wmake Making dependency list for source file yPlus.C could not open file basicPsiThermo.H for source file yPlus.C SOURCE=yPlus.C ; g++ -m64 -Dlinux64 -DWM_DP -Wall -Wextra -Wno-unused-parameter -Wold-style-cast -Wnon-virtual-dtor -O3 -DNoRepository -ftemplate-depth-100 -I/opt/openfoam220/src/meshTools/lnInclude -I/opt/openfoam220/src/transportModels -I/opt/openfoam220/src/turbulenceModels -I/opt/openfoam220/src/turbulenceModels/incompressible/RAS/derivedFvPatchFields/wallFunctions/nutWallFunctions -I/opt/openfoam220/src/turbulenceModels/compressible/RAS/derivedFvPatchFields/wallFunctions/mutWallFunctions -I/opt/openfoam220/src/thermophysicalModels/basic/lnInclude -I/opt/openfoam220/src/finiteVolume/lnInclude -IlnInclude -I. -I/opt/openfoam220/src/OpenFOAM/lnInclude -I/opt/openfoam220/src/OSspecific/POSIX/lnInclude -fPIC -c $SOURCE -o Make/linux64GccDPOpt/yPlus.o yPlus.C:37:28: fatal error: basicPsiThermo.H: No such file or directory compilation terminated. make: *** [Make/linux64GccDPOpt/yPlus.o] Error 1
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. Last edited by immortality; May 2, 2013 at 13:33. |
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May 2, 2013, 13:52
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#6 | |
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Senior Member
Mojtaba Amiraslanpour
Join Date: Jun 2011
Location: Tampa, US
Posts: 308
Rep Power: 16 |
Quote:
Which file did you use to compile?
__________________
Learn OpenFOAM in Persian SFO (StarCCM+ FLUENT OpenFOAM) Project Team Member Complex Heat & Flow Simulation Research Group If you can't explain it simply, you don't understand it well enough. "Richard Feynman" |
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May 2, 2013, 14:25
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#7 |
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Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 27 |
the second file he has put there.are they only for LES?
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. |
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May 2, 2013, 14:44
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#8 | |
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Senior Member
Mojtaba Amiraslanpour
Join Date: Jun 2011
Location: Tampa, US
Posts: 308
Rep Power: 16 |
Quote:
the uploaded file is the utility I used for incompressible flows using RAS models.
__________________
Learn OpenFOAM in Persian SFO (StarCCM+ FLUENT OpenFOAM) Project Team Member Complex Heat & Flow Simulation Research Group If you can't explain it simply, you don't understand it well enough. "Richard Feynman" |
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May 2, 2013, 15:47
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#9 |
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Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 27 |
it gives this error.maybe it should modified for 2.2.0 version.
Code:
ehsan@Ehsan-com:~/Desktop/yPlus$ wmake Making dependency list for source file yPlus.C could not open file nutWallFunctionFvPatchScalarField.H for source file yPlus.C could not open file basicPsiThermo.H for source file yPlus.C could not open file mutWallFunctionFvPatchScalarField.H for source file yPlus.C SOURCE=yPlus.C ; g++ -m64 -Dlinux64 -DWM_DP -Wall -Wextra -Wno-unused-parameter -Wold-style-cast -Wnon-virtual-dtor -O3 -DNoRepository -ftemplate-depth-100 -I/opt/openfoam220/src/meshTools/lnInclude -I/opt/openfoam220/src/transportModels -I/opt/openfoam220/src/turbulenceModels -I/opt/openfoam220/src/turbulenceModels/incompressible/RAS/derivedFvPatchFields/wallFunctions/nutWallFunctions -I/opt/openfoam220/src/turbulenceModels/compressible/RAS/derivedFvPatchFields/wallFunctions/mutWallFunctions -I/opt/openfoam220/src/thermophysicalModels/basic/lnInclude -I/opt/openfoam220/src/finiteVolume/lnInclude -IlnInclude -I. -I/opt/openfoam220/src/OpenFOAM/lnInclude -I/opt/openfoam220/src/OSspecific/POSIX/lnInclude -fPIC -c $SOURCE -o Make/linux64GccDPOpt/yPlus.o In file included from yPlus.C:35:0: /opt/openfoam220/src/turbulenceModels/incompressible/RAS/derivedFvPatchFields/wallFunctions/nutWallFunctions/nutkWallFunction/nutkWallFunctionFvPatchScalarField.H:56:47: fatal error: nutWallFunctionFvPatchScalarField.H: No such file or directory compilation terminated. make: *** [Make/linux64GccDPOpt/yPlus.o] Error 1
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. |
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May 2, 2013, 16:29
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#10 | |
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Senior Member
Mojtaba Amiraslanpour
Join Date: Jun 2011
Location: Tampa, US
Posts: 308
Rep Power: 16 |
Quote:
There is no nutWallFunctionFvPatchScalarField.H inside yPlus.C that it can't find. instead nutkWallFunctionFvPatchScalarField.H is used. Are you sure you are using the file I uploaded? I don't know if it has changed in OF 2.2 or not. maybe its dependency issues.
__________________
Learn OpenFOAM in Persian SFO (StarCCM+ FLUENT OpenFOAM) Project Team Member Complex Heat & Flow Simulation Research Group If you can't explain it simply, you don't understand it well enough. "Richard Feynman" |
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May 3, 2013, 08:55
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#11 |
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Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 27 |
yes.I use that file.
can anyone help how change it to adapt to 2.2.0 version?
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. |
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May 5, 2013, 09:44
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#12 |
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Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 27 |
in mutkWallFunctionFvPatchScalarField the equation uses for y-plus is related to y-star not y-plus
Code: Code:
y-star=pow(0.09,0.25)*sqr(k)*nearDist()/mu Code:
y-plus=rho*u_star*y/mu which u*=aqrt(taw_w/rho) in the code of mut : Code: Code:
forAll(mutw, faceI) { label faceCellI = patch().faceCells()[faceI]; scalar yPlus = Cmu25*y[faceI]*sqrt(k[faceCellI])/(muw[faceI]/rhow[faceI]); if (yPlus > yPlusLam_) { mutw[faceI] = muw[faceI]*(yPlus*kappa_/log(E_*yPlus) - 1); } }
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. |
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May 5, 2013, 14:41
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#13 |
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Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 27 |
could anyone have a look to resolve the error?
Code:
ehsan@Ehsan-com:~/Desktop/yPlus$ wmake /bin/sh: /home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/wmake/bin/linux64Gcc/wmkdep: not found SOURCE=yPlus.C ; g++ -m64 -Dlinux64 -DWM_DP -Wall -Wextra -Wno-unused-parameter -Wold-style-cast -Wnon-virtual-dtor -O3 -DNoRepository -ftemplate-depth-40 -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/meshTools/lnInclude -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/transportModels -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/turbulenceModels -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/turbulenceModels/incompressible/RAS/derivedFvPatchFields/wallFunctions/nutWallFunctions -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/turbulenceModels/compressible/RAS/derivedFvPatchFields/wallFunctions/mutWallFunctions -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/thermophysicalModels/basic/lnInclude -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/finiteVolume/lnInclude -IlnInclude -I. -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude -I/home/ehsan/OpenFOAM/OpenFOAM-1.6-ext/src/OSspecific/POSIX/lnInclude -fPIC -c $SOURCE -o Make/linux64GccDPOpt/yPlus.o yPlus.C:32:19: fatal error: fvCFD.H: No such file or directory compilation terminated. make: *** [Make/linux64GccDPOpt/yPlus.o] Error 1
__________________
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King. To Be or Not To Be,Thats the Question! The Only Stupid Question Is the One that Goes Unasked. |
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November 21, 2013, 03:11
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#14 |
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Member
India
Join Date: Oct 2012
Posts: 84
Rep Power: 14 |
Hi Mojtaba,
I used your yPlus utility. I ran a case using KKLOmega turbulence model with simpleFoam solver. I ran your yPlus utility after the simulation was completed. For every time step I am getting values of yPlus as "min=0, max=0, average=0". How to fix this? Also, the yPlusRAS utility that comes with OF-2.1.1 also has the problem of reporting y* instead of y+? Regards, Mayank |
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June 29, 2017, 11:58
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#15 |
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Senior Member
Yuehan
Join Date: Nov 2012
Posts: 142
Rep Power: 14 |
Hi,
My understanding of this issue is that the quantities of y-plus and y-star are approximately the same for equilibrium turbulent boundary layers. In equilibrium turbulent boundary layers, the friction velocity u_tau is approximately equal to Cmu^0.25*sqrt(k) in the log-law region, which is exactly the definition of u_star. However, in local non-equilibrium conditions such as separation and re-attachment, a deviation exists between u_tau and u_star, as u_tau is no longer approximately equal to Cmu^0.25*sqrt(k). I look forward to anyone correcting me if I am wrong here. |
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June 29, 2017, 12:14
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#16 |
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Senior Member
Yuehan
Join Date: Nov 2012
Posts: 142
Rep Power: 14 |
As regards OpenFOAM , nutLowReWallFunctions/mutLowReWallFunctions calculates y-plus according to the wall shear stress and the friction velocity. Other wall functions for nut/mut, such as mutkWallFunction, calculates y-plus in the way of calculating y-star.
You can borrow the code for the calculation of y-plus in nutLowReWallFunctionFvPatchScalarField.C/mutLowReWallFunctionFvPatchScalarField.C to write your own utility or function object to calculate y-plus. |
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December 6, 2017, 11:15
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#17 |
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Member
Lennart
Join Date: Feb 2016
Posts: 46
Rep Power: 10 |
Whether the utility calculates y+ or y* seems to depend on the OpenFOAM version you're using. The latest versions of both OpenFOAM and OpenFOAM+ seems to use the equation for y+. In older versions, it can be either y+, y* or depending on the turbulence model.
OpenFOAM 3.0.x: OpenFOAM-3.0.x/src/postProcessing/functionObjects/utilities/yPlus/yPlus.C in void Foam::yPlus::execute() Code:
const cmpModel& model =
mesh.lookupObject<cmpModel>(turbulenceModel::propertiesName);
calcYPlus(model, mesh, yPlus);
Code:
template<class TurbulenceModel>
void calcYPlus
(
const TurbulenceModel& turbulenceModel,
const fvMesh& mesh,
volScalarField& yPlus
);
OpenFOAM-4.x/src/functionObjects/field/yPlus/yPlus.C in void Foam::functionObjects::yPlus::calcYPlus(turbModel, mesh, yPlus) OpenFOAM-dev/src/functionObjects/field/yPlus/yPlus.C in void Foam::functionObjects::yPlus::calcYPlus(turbModel, yPlus) Code:
yPlusBf[patchi] =
d[patchi]
*sqrt
(
nuEffBf[patchi]
*mag(turbModel.U().boundaryField()[patchi].snGrad())
)/nuBf[patchi];
src/functionObjects/field/yPlus/yPlus.C in bool Foam::functionObjects::yPlus::execute() Code:
yPlusBf[patchi] =
d[patchi]
*sqrt
(
model.nuEff(patchi)
*mag(UBf[patchi].snGrad())
)/model.nu(patchi);
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April 21, 2019, 04:44
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#18 | |
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Senior Member
Jianrui Zeng
Join Date: May 2018
Location: China
Posts: 157
Rep Power: 8 |
Quote:
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