# How to exploit SGS kinetic energy with Smagorinsky model in LES

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

 November 3, 2014, 14:06 How to exploit SGS kinetic energy with Smagorinsky model in LES #1 Senior Member   Bobi Join Date: Oct 2012 Location: Chicago, Illinois Posts: 434 Rep Power: 9 Greetings Foamers I have performed a LES simulation in a cylindrical grid employing Smagorinsky model. I want to find out the quantity of the SGS kinetic energy. By searching a bit in this location: \$Foamsrc/ turbulenceModels/compressible/LES/Smagorinsky/Smagorinsky.H file in O.F-2.1.x, we can see that Code: \verbatim B = 2/3*k*I - 2*nuSgs*dev(D) where D = symm(grad(U)); k from rho*D:B + ce*rho*k^3/2/delta = 0 muSgs = ck*rho*sqrt(k)*delta \endverbatim and also Code:  //- Return SGS kinetic energy // calculated from the given velocity gradient tmp k(const tmp& gradU) const { volSymmTensorField D(symm(gradU)); volScalarField a(ce_/delta()); volScalarField b((2.0/3.0)*tr(D)); volScalarField c(2*ck_*delta()*(dev(D) && D)); return sqr((-b + sqrt(sqr(b) + 4*a*c))/(2*a)); } //- Return SGS kinetic energy The above lines point out that the SGS kinetic energy is computed in Smagorinsky approach. However, this variable is not written down during simulation. I have finished my simulation and I want to find a way to exploit this variable out of my results. I think the k file in 0 folder at the start of solution was SGS kinetic energy as well. Would somebody hint me that how can I exploit it out of my solution? Since the k file is no longer saved in time steps after starting solution. Best, Bobi

 November 10, 2014, 17:18 #2 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 10,125 Blog Entries: 39 Rep Power: 110 Hi Bobi, I can't think of a straight forward way of computing this, without coding. Therefore, I moved your thread to the programming sub-forum. You'll need look at least 2 utilities for ideas: "R" utility, located at "applications/utilities/postProcessing/turbulence/R" "yPlusLESWCompressible/yPlusLES.C", available here: https://github.com/wyldckat/yPlusLES...ble/tree/of21x The idea is that you need to call the method "k()", instead of "R()". But the detail is that the "R" utility is meant for RAS, which is why I mentioned "yPlusLESWCompressible". Best regards, Bruno babakflame and Uyan like this. __________________ OpenFOAM: FAQ | Getting started Forum: How to get help, to post code/output and forum guide What am I doing/planning: blog/wiki Read this before sending me PM

 November 11, 2014, 01:16 #3 Senior Member   Bobi Join Date: Oct 2012 Location: Chicago, Illinois Posts: 434 Rep Power: 9 Dear Bruno Many Thanks. I am going to look into your hints. Best Regards Bobi

 December 14, 2014, 07:58 #4 Senior Member   Bobi Join Date: Oct 2012 Location: Chicago, Illinois Posts: 434 Rep Power: 9 Dear Bruno I have been through your written utility:"yPlusLESWCompressible" I tried to do sth similar for the in Smagorinsky-based LES. However, it was a bit confusing for me . According to the formula : comes from combustion (flameletFoam), comes from LES simulation (compressible flow solver). is a constant parameter and is lesmodel::delta. Is it possible for you to write a similar utility as "yPlusLESWCompressible" for in Smagorinsky approach which would be very useful for students working with Smagorinsky-based LES approach? Just one point: Due to variations of thermodynamic formats between O.F 2.1.x and O.F. 2.3.x , Is it possible that the coming utility works with O.F. 2.1.x as well. Since lots of Foamers (like me) are still working with 2.1.x format. Best Regards, Bobi Last edited by babakflame; December 14, 2014 at 09:08.

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post hz283 OpenFOAM Running, Solving & CFD 12 January 18, 2017 13:01 Jan.Östh OpenFOAM Running, Solving & CFD 21 August 10, 2016 12:03 cfdmms Main CFD Forum 8 January 21, 2016 05:44 iyer_arvind OpenFOAM Running, Solving & CFD 26 September 9, 2014 07:22 Boerge FLUENT 1 September 8, 2012 11:41

All times are GMT -4. The time now is 09:49.