January 2017 - Nek5000-users - mailman3.cels.anl.gov

Setics subroutine in load_fld
by nek5000-users＠lists.mcs.anl.gov 02 Feb '17

02 Feb '17

Dear Neks, I am relatively new to NEK5000. I am going through some the .usr files that have been used previously in my research group. I notice that in the /userchk/ subroutine, /load_fld /has been called a few times. Upon checking the /load_fld/ function in in the source code, I found that /setics /subroutine is called at the end of /load_fld/ function. Does this mean that each time /load_fld /function is called, the /useric/ subroutine in the .usr file is executed? I would like to mention that no restart file is given in the .rea file. Many thanks. Best regards, Navrose.

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Multi-fluids simulation
by nek5000-users＠lists.mcs.anl.gov 31 Jan '17

31 Jan '17

Dear Nek users, Can Nek5000 simulate multi fluids? e.g. air blowing over water. It would be better if an example of the codes could be provided. Thank you, Peng

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Re: [Nek5000-users] Nek compiles on IBM, but not on Intel
by nek5000-users＠lists.mcs.anl.gov 26 Jan '17

26 Jan '17

Sorry for the inconvenience, we try hard not to break user space. The interpolation wrapper has been refactored and is no longer compiled by default. Add the following two pre-processor commands to the top of your .usr file #include "intp.f" #define INTP_MAXPTS 10000 Then, just call intp_setup(), intp_do(), intp_free(). Please note, that the API has changed. Same for g2gi() - grid to grid interpolation - which was replaced by our new generic fld reader gfldr() Cheers, Stefan -----Original message----- > From:[email protected] <nek5000-users(a)lists.mcs.anl.gov> > Sent: Thursday 26th January 2017 14:03 > To: nek5000-users(a)lists.mcs.anl.gov > Subject: Re: [Nek5000-users] Nek compiles on IBM, but not on Intel > > Ok, I found the error. For some reason, git pull created some empty files (drive?.f and others). A new git clone solved this. > A somewhat related question: Is it correct that the interpolation subroutines (intpts_ etc) have been removed from the latest release? I haven’t used them for some time but still had them in the usr file and noticed an error that they are missing. > > Jan > > Am 26.01.2017 um 09:39 schrieb nek5000-users(a)lists.mcs.anl.gov: > > > > Hi all, > > I am using Nek5000 for simulations on a Intel Xeon Westmere Cluster and on an IBM BlueGene/Q system. Both systesm have worked fine so far, but as of this morning, Nek suddenly stopped to compile on the Intel system. > > On the IBM system, I use the mpixlf77, mpixlc compilers and both my own cases and the examples compile. > > On the Intel system, I use the mpiifort, mpiicc (version 16.0.1) compilers and compiling stops with the message > > drive1.f: fatal: can't fgets from file: drive1.f > > drive2.f: fatal: can't fgets from file: drive2.f > > Both systems are using the current version from github and exactly the same .usr files. > > Has there been any update to Nek or the intel compilers that might cause this problem? I just tried the 16.0.3 version (the newest installed from Intel) and the error persisted. > > Thanks in advance for any thougts on this, > > Jan > > _______________________________________________ > > 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 >

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Nek compiles on IBM, but not on Intel
by nek5000-users＠lists.mcs.anl.gov 26 Jan '17

26 Jan '17

Hi all, I am using Nek5000 for simulations on a Intel Xeon Westmere Cluster and on an IBM BlueGene/Q system. Both systesm have worked fine so far, but as of this morning, Nek suddenly stopped to compile on the Intel system. On the IBM system, I use the mpixlf77, mpixlc compilers and both my own cases and the examples compile. On the Intel system, I use the mpiifort, mpiicc (version 16.0.1) compilers and compiling stops with the message drive1.f: fatal: can't fgets from file: drive1.f drive2.f: fatal: can't fgets from file: drive2.f Both systems are using the current version from github and exactly the same .usr files. Has there been any update to Nek or the intel compilers that might cause this problem? I just tried the 16.0.3 version (the newest installed from Intel) and the error persisted. Thanks in advance for any thougts on this, Jan

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Re: [Nek5000-users] nelgv in uservp of conj_ht
by nek5000-users＠lists.mcs.anl.gov 24 Jan '17

24 Jan '17

Case (1) is correct way to impose properties for the solid. The interface condition will match the fluxes (in a weak sense) while heat capacity can discontinuous. -----Original message----- > From:[email protected] <nek5000-users(a)lists.mcs.anl.gov> > Sent: Tuesday 24th January 2017 17:28 > To: nek5000-users(a)lists.mcs.anl.gov > Subject: [Nek5000-users] nelgv in uservp of conj_ht > > Hello All, > I have a question in uservp of conjugate heat transfer. I am trying to modify the conjugate heat transfer problem (with additional passive scalars) and use for solving MHD problem with vector potential approach. > > I tested the conjugate heat transfer case changing the IF condition in uservp in following ways. > > Case 1: > if (ieg .gt. nelgv) then ! properties in the solid > udiff = 0.1*param(8) ! conductivity > utrans = 1.0 > endif > > Case 2: > if (y .ge. 1.5D0) then > udiff= 0.1*param(8) > elseif (y. le. 0.5D0) then > udiff= 0.1*param(8) > else > udiff = param(8) > endif > > I got a small difference in the temperature profile at the interface between solid and fluid. > Could you please let me know, how do the above two cases affect the conditions imposed at the interface (what is the mathematical treatment and how does it change). > Thank you in advance. > > Yours sincerely, > Sandeep > _______________________________________________ > Nek5000-users mailing list > Nek5000-users(a)lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users

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nelgv in uservp of conj_ht
by nek5000-users＠lists.mcs.anl.gov 24 Jan '17

24 Jan '17

Hello All, I have a question in uservp of conjugate heat transfer. I am trying to modify the conjugate heat transfer problem (with additional passive scalars) and use for solving MHD problem with vector potential approach. I tested the conjugate heat transfer case changing the IF condition in uservp in following ways. Case 1: if (ieg .gt. nelgv) then ! properties in the solid udiff = 0.1*param(8) ! conductivity utrans = 1.0 endif Case 2: if (y .ge. 1.5D0) then udiff= 0.1*param(8) elseif (y. le. 0.5D0) then udiff= 0.1*param(8) else udiff = param(8) endif I got a small difference in the temperature profile at the interface between solid and fluid. Could you please let me know, how do the above two cases affect the conditions imposed at the interface (what is the mathematical treatment and how does it change). Thank you in advance. Yours sincerely, Sandeep

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Re: [Nek5000-users] Convergence problem in 2D square cylinder
by nek5000-users＠lists.mcs.anl.gov 24 Jan '17

24 Jan '17

Thank you Tanmoy and Paul. I have redone the mesh. I do not know why, but less layers in the boundary helped to stabilize the convergence. I have also played around with parameters 101 and 103. However, I should check wether the dynamics have changed or not. VBeltranM -- Víctor Beltrán Martínez Ph.D. Student in Applied Mathematics Escuela Técnica Superior de Ingeniería Aeronáutica y del Espacio Universidad Politécnica de Madrid

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Re: [Nek5000-users] double mesh ?
by nek5000-users＠lists.mcs.anl.gov 21 Jan '17

21 Jan '17

Dear Paul thank you so much for your help ! I am looking forward to see your example, it will be of great help ! could you tell me something more about the recycling BC as well ? Thank you again for your help Agnese > > From: nek5000-users(a)lists.mcs.anl.gov <mailto:[email protected]> > Subject: Re: [Nek5000-users] double mesh ? > Date: January 16, 2017 at 4:05:21 PM GMT+1 > To: "nek5000-users(a)lists.mcs.anl.gov <mailto:[email protected]>" <nek5000-users(a)lists.mcs.anl.gov <mailto:[email protected]>> > Reply-To: nek5000-users(a)lists.mcs.anl.gov <mailto:[email protected]> > > Dear Agnese, > > Sorry for the long delay in answering this question. The issue is that in fact it is possible > (and used to be a supported but rarely used feature). The challenge, however, is how to > make it relatively easy in the context of the current setup for a variety of applications. > > Nek supports a different gather-scatter handle for each field (velocity, temperature, passive > scalar, etc.) > > We have a handle that allows the user access to the connectivity list, which would give > you an opportunity to "disconnect" the periodic faces for the temperature array. > > I'll try to code up an example for the case of channel flow with a mesh generated by > genbox and post it shortly. > > Incidentally, an alternative approach that we often use for more complex domains > would be to use a recycling boundary condition. I think it would not be as efficient, > however, as periodicity for the case that you propose. > > Once again, apologies for the delayed response. > > 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: Thursday, December 22, 2016 4:38 AM > To: nek5000-users(a)lists.mcs.anl.gov <mailto:[email protected]> > Subject: [Nek5000-users] double mesh ? > > Hi > > i am quite new, so i’m sorry if i’m getting things wrong. > > I am trying to simulate a turbulent channel flow, with a passive scalar. > in the streamwise direction, i would like to impose periodic boundary conditions for the flow, and non-periodic for the scalar. > in fact the scalar has a point source near the inlet, and i want to see how that develops downstream. > > as far as i understand this is not supported by nek5000, because the last mesh point is identified with the first mesh point when periodic BC are imposed. > correct ? > > my question is : could i define two meshes, one for the scalar and one for the velocity ? > > thanks a lot for your help !!! > agnese > > > Agnese Seminara > -------------------------------- > CNRS > Laboratoire de physique de la matière condensée > Parc Valrose > avenue J Vallot > 06108 Nice, France > +33 (0) 492 076 775 > http://sites.unice.fr/site/aseminara/ <http://sites.unice.fr/site/aseminara/> > > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users(a)lists.mcs.anl.gov <mailto:[email protected]> > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users <https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users>

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Re: [Nek5000-users] mesh smoothing
by nek5000-users＠lists.mcs.anl.gov 19 Jan '17

19 Jan '17

Hi Dillon, I have a mesh smoother. Can you email me on kmittal2(a)illinois.edu and we can discuss the smoother over there. Ketan

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mesh smoothing
by nek5000-users＠lists.mcs.anl.gov 19 Jan '17

19 Jan '17

Greetings Nekians, Rumor on the street is there are some mesh smoothing algorithms available. We've been experiencing some problems with high pressure iteration counts and one of our current suspects is a poor quality mesh. Any help would be appreciated! Thank you, Dillon

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