December 2015 - Nek5000-users - mailman3.cels.anl.gov

Re: [Nek5000-users] Vorticity
by nek5000-users＠lists.mcs.anl.gov 11 Oct '16

11 Oct '16

Hi, Thanks for your quick reply. Just I wanna know if I can use the interpolated values of velocity at some arbitrary points in the domain (not necessarily the grid points) as the input arguments to theses subroutines. Regards, Alireza Quoting nek5000-users-request(a)lists.mcs.anl.gov: > Send Nek5000-users mailing list submissions to > nek5000-users(a)lists.mcs.anl.gov > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > or, via email, send a message with subject or body 'help' to > nek5000-users-request(a)lists.mcs.anl.gov > > You can reach the person managing the list at > nek5000-users-owner(a)lists.mcs.anl.gov > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Nek5000-users digest..." > > > Today's Topics: > > 1. Vorticity (nek5000-users(a)lists.mcs.anl.gov) > 2. Re: Vorticity (nek5000-users(a)lists.mcs.anl.gov) > 3. Re: Vorticity (nek5000-users(a)lists.mcs.anl.gov) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 13 Jul 2011 17:55:35 -0400 > From: nek5000-users(a)lists.mcs.anl.gov > Subject: [Nek5000-users] Vorticity > To: nek5000-users(a)lists.mcs.anl.gov > Message-ID: <20110713175535.1042430oct81vz2v(a)webmail.vt.edu> > Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes"; > format="flowed" > > Hi, > > I need to calculate the vorticity vector and the rate of strain tensor > at any arbitrary point in the domain. I wonder if these values are > computed somewhere in the code or if I should interpolate them in the > usr file. I appreciate any kind of help. > > Thanks in advance, > > > Regards, > Alireza Karimi > > > > ------------------------------ > > Message: 2 > Date: Wed, 13 Jul 2011 17:09:48 -0500 (CDT) > From: nek5000-users(a)lists.mcs.anl.gov > Subject: Re: [Nek5000-users] Vorticity > To: nek5000-users(a)lists.mcs.anl.gov > Message-ID: <Pine.LNX.4.64.1107131704140.26989(a)jacobi.mcs.anl.gov> > Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed > > Hi Alireza, > > For vorticity computation, you can call > > call comp_vort3(vort,work1,work2,vx,vy,vz) > > from userchk with the appropriate definitions of vorticity and work arrays > like > > common /scren/ vort (lx1,ly1,lz1,lelv,3) ! x y z components > $ , work1(lx1,ly1,lz1,lelv) > $ , work2(lx1,ly1,lz1,lelv) > > Let me check what we have for the calculation of strain tensor. > Best, > Aleks > > > On Wed, 13 Jul 2011, nek5000-users(a)lists.mcs.anl.gov wrote: > >> Hi, >> >> I need to calculate the vorticity vector and the rate of strain >> tensor at any >> arbitrary point in the domain. I wonder if these values are computed >> somewhere in the code or if I should interpolate them in the usr file. I >> appreciate any kind of help. >> >> Thanks in advance, >> >> >> Regards, >> Alireza Karimi >> >> _______________________________________________ >> Nek5000-users mailing list >> Nek5000-users(a)lists.mcs.anl.gov >> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > > > ------------------------------ > > Message: 3 > Date: Wed, 13 Jul 2011 23:59:08 -0500 (CDT) > From: nek5000-users(a)lists.mcs.anl.gov > Subject: Re: [Nek5000-users] Vorticity > To: nek5000-users(a)lists.mcs.anl.gov > Message-ID: > <600285192.94128.1310619548370.JavaMail.root(a)zimbra.anl.gov> > Content-Type: text/plain; charset=utf-8 > > Hi Alireza, > > > For a strain stress computation you can call subroutine comp_sij > > call comp_sij(sij,nij,vx,vy,vz > $ ,ur,us,ut,vr,vs,vt,wr,ws,wt) > > > (navier5.f:2225) with nij=6 for 3D somewhere from userchk once you > declare the stress component array sij and arrays with local > coordinate r-s-t derivatives of velocity components > > common /csij/ > $ sij(lx1*ly1*lz1,6,lelv) ! 6 components > $ ,ur (lx1*ly1*lz1) > ... > $ ,wt (lx1*ly1*lz1) > > > Best, > Aleks > > > > > > > ----- Original Message ----- > From: nek5000-users(a)lists.mcs.anl.gov > To: nek5000-users(a)lists.mcs.anl.gov > Sent: Wednesday, July 13, 2011 5:09:48 PM > Subject: Re: [Nek5000-users] Vorticity > > Hi Alireza, > > For vorticity computation, you can call > > call comp_vort3(vort,work1,work2,vx,vy,vz) > > from userchk with the appropriate definitions of vorticity and work arrays > like > > common /scren/ vort (lx1,ly1,lz1,lelv,3) ! x y z components > $ , work1(lx1,ly1,lz1,lelv) > $ , work2(lx1,ly1,lz1,lelv) > > Let me check what we have for the calculation of strain tensor. > Best, > Aleks > > > On Wed, 13 Jul 2011, nek5000-users(a)lists.mcs.anl.gov wrote: > >> Hi, >> >> I need to calculate the vorticity vector and the rate of strain >> tensor at any >> arbitrary point in the domain. I wonder if these values are computed >> somewhere in the code or if I should interpolate them in the usr file. I >> appreciate any kind of help. >> >> Thanks in advance, >> >> >> Regards, >> Alireza Karimi >> >> _______________________________________________ >> Nek5000-users mailing list >> Nek5000-users(a)lists.mcs.anl.gov >> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > _______________________________________________ > Nek5000-users mailing list > Nek5000-users(a)lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > > > ------------------------------ > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users(a)lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > > > End of Nek5000-users Digest, Vol 29, Issue 2 > ******************************************** > -- Alireza Karimi PhD Candidate Department of Engineering Science and Mechanics Virginia Polytechnic Institute and State University Blacksburg, VA 24061

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Error when creating own mesh
by nek5000-users＠lists.mcs.anl.gov 01 Mar '16

01 Mar '16

Dear Neks, I am have attempted to use nek5000, firstly by following some of the examples etc. Now I am trying to create my own simulation, which is based upon the ocyl examples. My efforts simply include creating my own grid points in the .rea file to create a slightly different dimension... I believe I have understood how to define the problem however I continually receive errors when creating the genmap it reads as follows.... Input (.rea) file name: ocyl Input mesh tolerance (default 0.2): NOTE: smaller is better, but generous is more forgiving for bad meshes. 0.2 reading .rea file data ... ERROR: error reading 1 11 24 aborting 510 in routine rdbdry. 1 quit All I have done again is change the dimensions of the elements in the .rea file so I do not see why it would now not work? Thank you for any help in advance, Friedrich.

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Stress formulation
by nek5000-users＠lists.mcs.anl.gov 05 Jan '16

05 Jan '16

Hi Neks, I have one question about stress formulation in NEK5000. I tried to make a simulation for Poiseuil flow with stress formulation. In inlet boundary condition use was made of parabolic profile. If IFSTRS=false the outlet profile is exactly the same as inlet one but in case of IFSTRS=true the outlet profile changes significantly (both the maximum value and profile shape). Could you tell me how I can get the parabolic profile at outlet, please? The same thing occurs with pressure values. The maximum pressure value with IFSTRS=true is three times higher then the one with IFSTRS=false. I found that the difference comes from subroutines where the stiffness matrix is calculated (axehlm for IFSTRS = false and axhmsf for IFSTRS = true) but I don't undestand what is happening exactly. Thanks in advance for your help, Best regards, Andrew

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Sym boundary condition in mshconvert file
by nek5000-users＠lists.mcs.anl.gov 31 Dec '15

31 Dec '15

Hi Neks, I have downloaded the program mshconvert file to convert my Fluent mesh to nek5000 format. It works well with normal boundary conditions like W,v and O where W is wall, v is inlet velocity and O is outlet. However, the I am unable to prescribe symmetry, SYM as the code only takes the last letter (for this case, M). Any of you facing this problem and is there a way around this? Rif

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Coriolis Force
by nek5000-users＠lists.mcs.anl.gov 29 Dec '15

29 Dec '15

Hi Neks, I tried to include a rotation in my simulation for a flat plate by introducing a Coriolis term in the subroutine *userf* like so : --------------------------------------------------------------------------------------- subroutine userf (ix,iy,iz,eg) include 'SIZE' include 'TOTAL' include 'NEKUSE' integer e,f,eg e = gllel(eg) Omega= 2 ffx = +2.0*Omega*vy ffy = -2.0*Omega*vx ffz = 0.0 return end ----------------------------------------------------------------------------------------------- PROBLEM: When i tried compiling, it gives me an error ERROR: Incompatible ranks 0 and 4 in assignment at (1) Is there a way out of this? Does this have something to do with assigning a scalar to an array? if so how do I get past this? Rif

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Grid 2 Grid Interpolation
by nek5000-users＠lists.mcs.anl.gov 24 Dec '15

24 Dec '15

Hi Neks, I am using the routine " Grid 2 Grid Interpolation <http://lists.mcs.anl.gov/pipermail/nek5000-users/2010-September/001004.html>" , it does interpolate data between two meshes, but there is another problem: Both the "base.fld" and "new_geo.fld" are double-precision, however, the interpolated "new.fld" is single precision. show the head here: #std 4 8 8 8 31200 31200 0.1969999999996E+03 0 0 1 XUPT - I have already active the parameter(63) to 8, trying to save the double-precision result. Any one have a solution? thanks! Wei -

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Re: [Nek5000-users] Stress formulation
by nek5000-users＠lists.mcs.anl.gov 17 Dec '15

17 Dec '15

Hi Andrew Are you running the "axi" case in the examples? This case started with u=0 as an initial condition. A quick glance at the output it produces in f00004, after 200 steps, shows plots similar to yours. If you run longer (change nsteps in the .rea file), the viscous boundary layer will diffuse inward from the walls and you should see a parabolic profile. This is what I observed just now. Please let me know if this resolves the issue --- if not, I'm happy to check further. Best, Paul ________________________________ From: Andrey Souchkov [andrey.souchkov(a)gmail.com] Sent: Thursday, December 17, 2015 7:07 PM To: nek5000-users(a)lists.mcs.anl.gov Subject: Re: [Nek5000-users] Stress formulation Hi Paul, I think I have misspoken. The thing is that I haven't got the profile corresponding to the inlet one anywhere in pipe. I add some clarifications. You can find attached file with velocity curves for my simulaltions. I have done the simulations of Poiseuille flow in the cylindrical pipe. With IFAXIS = true, IFSTRS = false, param (30) = 0 the input profile doesn't chage. With IFAXIS = true, IFSTSR = true, param (30) = 0 the input velocity profile changes considerably along the pipe and on the axis there is strange pressure peak, the nature of which I can not understand. Can I have clarification on this question? Thanks, Andrew 2015-12-14 0:55 GMT+01:00 <nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]>>: Hi Andrew, In my view, you are already getting the correct flow physics. What happens at outflow, especially at moderate Reynolds number, is not necessarily parallel flow. The stress formulation is giving the stress-free result. Paul ________________________________ From: nek5000-users-bounces(a)lists.mcs.anl.gov<mailto:[email protected]> [nek5000-users-bounces(a)lists.mcs.anl.gov<mailto:[email protected]>] on behalf of nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]> [nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]>] Sent: Sunday, December 13, 2015 5:19 PM To: nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]> Subject: Re: [Nek5000-users] Stress formulation Hi Paul, Thank you for your reply. Yes, if i increase Reynolds number, the outlet profile become much close to the inlet one. But in my simulations the Reynolds number is between 300 and 1200. Can you recommend me what kind of boundary conditions i can utilise for ensure for ensure the flow physics ? I would implement these one in code. Thanks, Andrew 2015-12-05 3:37 GMT+01:00 <nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]>>: Hi Andrew, I checked into this... I think what is happening is that the 'O ' bc for the stress formulation means stress-free, which is not guaranteed to yield a parabolic profile at the outlet. If you increase your Reynolds number I'm guessing that you'll recover the parabolic profile because the viscous stresses will diminish -- this is what I observed. >From my perspective, the outlet boundary is not a region where I would count on accurate physics --- it is, after all, a truncated domain, so I don't generally worry too much about the behavior there. Paul ________________________________ From: nek5000-users-bounces(a)lists.mcs.anl.gov<mailto:[email protected]> [nek5000-users-bounces(a)lists.mcs.anl.gov<mailto:[email protected]>] on behalf of nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]> [nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]>] Sent: Tuesday, December 01, 2015 2:44 AM To: nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]> Subject: [Nek5000-users] Stress formulation Hi Neks, I have one question about stress formulation in NEK5000. I tried to make a simulation for Poiseuil flow with stress formulation. In inlet boundary condition use was made of parabolic profile. If IFSTRS=false the outlet profile is exactly the same as inlet one but in case of IFSTRS=true the outlet profile changes significantly (both the maximum value and profile shape). Could you tell me how I can get the parabolic profile at outlet, please? The same thing occurs with pressure values. The maximum pressure value with IFSTRS=true is three times higher then the one with IFSTRS=false. I found that the difference comes from subroutines where the stiffness matrix is calculated (axehlm for IFSTRS = false and axhmsf for IFSTRS = true) but I don't undestand what is happening exactly. Thanks in advance for your help, Best regards, Andrew _______________________________________________ Nek5000-users mailing list Nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users _______________________________________________ Nek5000-users mailing list Nek5000-users(a)lists.mcs.anl.gov<mailto:[email protected]> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users

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Re: [Nek5000-users] freestream turbulence at INLET
by nek5000-users＠lists.mcs.anl.gov 17 Dec '15

17 Dec '15

Hi Ricardo, Thanks for the paper. Were you in Canmore for the CFD challenge? I was there as well! My prof organized that event. Small world. Cheers Rif

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problems genbox
by nek5000-users＠lists.mcs.anl.gov 16 Dec '15

16 Dec '15

Sorry, I forgot the object -- Mr. Mirko FaranoPh.D. student at Politecnico di BariTel.: +39-0883529289 / +39-0805963462Mob.: +39-3202342719Department of Mechanics Mathematics and Management - Fluid Machinery and Energy SystemsVia Re David, 200 - 70125 Bari (Italy)mirko.farano(a)poliba.itIn joint supervision with theEcole Nationale Supérieure d'Arts et Métiers de Paris - ParistechTel.: +33-144246436Mob.: +33-789822134Dynfluid Laboratory151 Boulevard de l'Hôpital - 75013 Paris (France)mirko.farano(a)ensam.eu ----Messaggio originale---- Da: nek5000-users(a)lists.mcs.anl.gov Data: 16-dic-2015 20.41 A: <nek5000-users(a)lists.mcs.anl.gov> Ogg: [Nek5000-users] (no subject) Hi nek's I'm trying to perform a DNS of a turbulent channel flow ussing the tutorial "turbChannel.f". I have some troubles about the subroutine "planar_average_s", in particular when I generate a mesh using genbox in a single box, it works very well, such that the vector "yy" goes from -1 to 1. On the contrary when i split the box in genbox in two boxes, "yy" goes from -0.5 to 0.5 and it is repeated two rimes (-0.5, ... 0.5, -0.5, ..., 0.5), of course the averages have no sense. Could someone help me? Thanks --------------------------------------------------------------------------------------------------------- Box 1 -48 16 -48 nelx,nely,nelz for Box 0.0 6.28 1. x0,x1,gain -1. -.999 -.998 -.995 -.988 -.974 -.943 -.877 -.780 -.682 -.584 -.487 -.389 -.292 -.194 -.096 0.0 0.0 3.14 1. z0,z1,gain P ,P ,W ,E ,P ,P bc's (3 chars each!) Box 2 -48 16 -48 nelx,nely,nelz for Box 0.0 6.28 1. x0,x1,gain 0.0 .096 .194 .292 .389 .487 .584 .682 .780 .877 .943 .974 .988 .995 .998 .999 1. 0.0 3.14 1. z0,z1,gain P ,P ,E ,W ,P ,P bc's (3 chars each!) ---------------------------------------------------------------------------------------------------------- -- Mr. Mirko FaranoPh.D. student at Politecnico di BariTel.: +39-0883529289 / +39-0805963462Mob.: +39-3202342719Department of Mechanics Mathematics and Management - Fluid Machinery and Energy SystemsVia Re David, 200 - 70125 Bari (Italy)mirko.farano(a)poliba.itIn joint supervision with theEcole Nationale Supérieure d'Arts et Métiers de Paris - ParistechTel.: +33-144246436Mob.: +33-789822134Dynfluid Laboratory151 Boulevard de l'Hôpital - 75013 Paris (France)mirko.farano(a)ensam.eu

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(no subject)
by nek5000-users＠lists.mcs.anl.gov 16 Dec '15

16 Dec '15

Hi nek's I'm trying to perform a DNS of a turbulent channel flow ussing the tutorial "turbChannel.f". I have some troubles about the subroutine "planar_average_s", in particular when I generate a mesh using genbox in a single box, it works very well, such that the vector "yy" goes from -1 to 1. On the contrary when i split the box in genbox in two boxes, "yy" goes from -0.5 to 0.5 and it is repeated two rimes (-0.5, ... 0.5, -0.5, ..., 0.5), of course the averages have no sense. Could someone help me? Thanks --------------------------------------------------------------------------------------------------------- Box 1 -48 16 -48 nelx,nely,nelz for Box 0.0 6.28 1. x0,x1,gain -1. -.999 -.998 -.995 -.988 -.974 -.943 -.877 -.780 -.682 -.584 -.487 -.389 -.292 -.194 -.096 0.0 0.0 3.14 1. z0,z1,gain P ,P ,W ,E ,P ,P bc's (3 chars each!) Box 2 -48 16 -48 nelx,nely,nelz for Box 0.0 6.28 1. x0,x1,gain 0.0 .096 .194 .292 .389 .487 .584 .682 .780 .877 .943 .974 .988 .995 .998 .999 1. 0.0 3.14 1. z0,z1,gain P ,P ,E ,W ,P ,P bc's (3 chars each!) ---------------------------------------------------------------------------------------------------------- -- Mr. Mirko FaranoPh.D. student at Politecnico di BariTel.: +39-0883529289 / +39-0805963462Mob.: +39-3202342719Department of Mechanics Mathematics and Management - Fluid Machinery and Energy SystemsVia Re David, 200 - 70125 Bari (Italy)mirko.farano(a)poliba.itIn joint supervision with theEcole Nationale Supérieure d'Arts et Métiers de Paris - ParistechTel.: +33-144246436Mob.: +33-789822134Dynfluid Laboratory151 Boulevard de l'Hôpital - 75013 Paris (France)mirko.farano(a)ensam.eu

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