From nek5000-users at lists.mcs.anl.gov Mon Dec 1 19:26:50 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Mon, 1 Dec 2014 19:26:50 -0600 Subject: [Nek5000-users] mesh of solid example Message-ID: Hi, I am new to nek5000, How do they generated mesh example "solid"? ie, is this was generated with GENBOX tool (Annulus Geometry)? I tried repoducir this geometry but I have not succeeded, would it be possible to see a name.box about this example? Best Regards, sasaan -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Thu Dec 4 20:03:32 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Thu, 4 Dec 2014 21:03:32 -0500 Subject: [Nek5000-users] auto_averager() Message-ID: Hello all, I am trying to take an average from previously averaged output "avgblah.f" files using the following calls in userchk in postprocessing mode: ... call auto_averager(filename) call outpost(vx,vy,vz,pr,t,'AVG') call exitti('exiting AVG routine$',icount) ... While I got the correct velocity field average, the average for the temperature field is not correct, as it is out of min/max range in the output files. I went through the "auto_averager" routine, but couldn't find anything wrong with that. So I was wondering if anyone has any thought on this issue that can help me. Thanks, Mohsen From nek5000-users at lists.mcs.anl.gov Thu Dec 4 21:31:54 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Fri, 5 Dec 2014 03:31:54 +0000 Subject: [Nek5000-users] auto_averager() In-Reply-To: References: Message-ID: Hi Mohsen, I would suggest checking the range of the temperature inputs as they are read in auto_averager and then checking the range of the averages. Something like: tmax = glmax(t,n) tmin = glmin(t,n) if (nid.eq.0) write(6,*) k,tmin,tmax,' tmin' would produce those values... then you can do something similar for the averaged result. Perhaps the failure occurs during the read process ... or.. etc. Paul ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] Sent: Thursday, December 04, 2014 8:03 PM To: nek5000-users at lists.mcs.anl.gov Subject: [Nek5000-users] auto_averager() Hello all, I am trying to take an average from previously averaged output "avgblah.f" files using the following calls in userchk in postprocessing mode: ... call auto_averager(filename) call outpost(vx,vy,vz,pr,t,'AVG') call exitti('exiting AVG routine$',icount) ... While I got the correct velocity field average, the average for the temperature field is not correct, as it is out of min/max range in the output files. I went through the "auto_averager" routine, but couldn't find anything wrong with that. So I was wondering if anyone has any thought on this issue that can help me. Thanks, Mohsen _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users From nek5000-users at lists.mcs.anl.gov Fri Dec 5 13:18:00 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Fri, 5 Dec 2014 14:18:00 -0500 Subject: [Nek5000-users] auto_averager() In-Reply-To: References: Message-ID: Thanks Paul for your suggestion. The failure occurs due to common block /scrns/ with array "ta" in auto_averager. This block is also shared with the "restart" routine, in which new values are apparently reassigned to it after each call. It is solved by either defining a new block or moving "ta" to block / scruz/. Mohsen On 4-Dec-14, at 10:31 PM, wrote: > > Hi Mohsen, > > I would suggest checking the range of the temperature inputs as > they are read > in auto_averager and then checking the range of the averages. > > Something like: > > tmax = glmax(t,n) > tmin = glmin(t,n) > if (nid.eq.0) write(6,*) k,tmin,tmax,' tmin' > > would produce those values... then you can do something > similar for the averaged result. > > Perhaps the failure occurs during the read process ... or.. etc. > > Paul > > ________________________________________ > From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users- > bounces at lists.mcs.anl.gov] on behalf of nek5000- > users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] > Sent: Thursday, December 04, 2014 8:03 PM > To: nek5000-users at lists.mcs.anl.gov > Subject: [Nek5000-users] auto_averager() > > Hello all, > I am trying to take an average from previously averaged output > "avgblah.f" files using the following calls in userchk in > postprocessing > mode: > > ... > call auto_averager(filename) > call outpost(vx,vy,vz,pr,t,'AVG') > call exitti('exiting AVG routine$',icount) > ... > > While I got the correct velocity field average, the average for the > temperature field is not correct, as it is out of min/max range in the > output files. I went through the "auto_averager" routine, but couldn't > find anything wrong with that. > > So I was wondering if anyone has any thought on this issue that can > help me. > > Thanks, > Mohsen > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users From nek5000-users at lists.mcs.anl.gov Fri Dec 5 15:06:20 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Fri, 5 Dec 2014 21:06:20 +0000 Subject: [Nek5000-users] auto_averager() In-Reply-To: References: , Message-ID: Thanks Mohsen.... I'll take care of that. Paul ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] Sent: Friday, December 05, 2014 1:18 PM To: nek5000-users at lists.mcs.anl.gov Subject: Re: [Nek5000-users] auto_averager() Thanks Paul for your suggestion. The failure occurs due to common block /scrns/ with array "ta" in auto_averager. This block is also shared with the "restart" routine, in which new values are apparently reassigned to it after each call. It is solved by either defining a new block or moving "ta" to block / scruz/. Mohsen On 4-Dec-14, at 10:31 PM, wrote: > > Hi Mohsen, > > I would suggest checking the range of the temperature inputs as > they are read > in auto_averager and then checking the range of the averages. > > Something like: > > tmax = glmax(t,n) > tmin = glmin(t,n) > if (nid.eq.0) write(6,*) k,tmin,tmax,' tmin' > > would produce those values... then you can do something > similar for the averaged result. > > Perhaps the failure occurs during the read process ... or.. etc. > > Paul > > ________________________________________ > From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users- > bounces at lists.mcs.anl.gov] on behalf of nek5000- > users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] > Sent: Thursday, December 04, 2014 8:03 PM > To: nek5000-users at lists.mcs.anl.gov > Subject: [Nek5000-users] auto_averager() > > Hello all, > I am trying to take an average from previously averaged output > "avgblah.f" files using the following calls in userchk in > postprocessing > mode: > > ... > call auto_averager(filename) > call outpost(vx,vy,vz,pr,t,'AVG') > call exitti('exiting AVG routine$',icount) > ... > > While I got the correct velocity field average, the average for the > temperature field is not correct, as it is out of min/max range in the > output files. I went through the "auto_averager" routine, but couldn't > find anything wrong with that. > > So I was wondering if anyone has any thought on this issue that can > help me. > > Thanks, > Mohsen > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users From nek5000-users at lists.mcs.anl.gov Wed Dec 10 10:23:02 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Wed, 10 Dec 2014 16:23:02 +0000 Subject: [Nek5000-users] Unrealistic values at element edges Message-ID: Dear Neks, I've been running turbulent channel and pipe flows using nek5000 for a while. However, recently when I created movies of lambda2 structures and pressure iso-surfaces in channel and pipe flows I observed some "strange" values at the edge between elements. [cid:cec5092f-41be-4ae9-a468-a5fa9ab9f7ff] This is lambda2 structures in turbulent pipe flow. It is clearly visible from the picture that at some slices in streamwise direction, the values don't seem to be realistic and it feels like the flow is passing through some filters. Interestingly, when I plotted the mesh together with the variables, the vertical noise lines happened to be at the edge between adjacent elements, which is particularly clear in lambda2 plot. Same behaviour was also found in 2D pressure plots and in turbulent channel flow cases. Has anyone observed similar things before in visualisation? I used both Paraview and VisIt for visualisation and the same thing was observed, so it shouldn't be a problem of software. In this case, I'm just wondering why the result is like this or is it because I set something wrong in my simulations? Any comments will be appreciated and thank you very much in advance. Best regards, Tony -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: l2.jpg Type: image/jpeg Size: 66013 bytes Desc: l2.jpg URL: From nek5000-users at lists.mcs.anl.gov Wed Dec 10 10:28:55 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Wed, 10 Dec 2014 16:28:55 +0000 Subject: [Nek5000-users] Unrealistic values at element edges In-Reply-To: References: Message-ID: Dear Neks, Sorry that the image wasn't shown. I've attached it here. Hope someone can help. Thanks and regards, Tony ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov on behalf of nek5000-users-request at lists.mcs.anl.gov Sent: 10 December 2014 16:23 To: nek5000-users at lists.mcs.anl.gov Subject: Nek5000-users Digest, Vol 70, Issue 4 Send Nek5000-users mailing list submissions to nek5000-users at 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 at lists.mcs.anl.gov You can reach the person managing the list at nek5000-users-owner at 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. Unrealistic values at element edges (nek5000-users at lists.mcs.anl.gov) ---------------------------------------------------------------------- Message: 1 Date: Wed, 10 Dec 2014 16:23:02 +0000 From: nek5000-users at lists.mcs.anl.gov To: "nek5000-users at lists.mcs.anl.gov" Subject: [Nek5000-users] Unrealistic values at element edges Message-ID: Content-Type: text/plain; charset="iso-8859-1" Dear Neks, I've been running turbulent channel and pipe flows using nek5000 for a while. However, recently when I created movies of lambda2 structures and pressure iso-surfaces in channel and pipe flows I observed some "strange" values at the edge between elements. [cid:cec5092f-41be-4ae9-a468-a5fa9ab9f7ff] This is lambda2 structures in turbulent pipe flow. It is clearly visible from the picture that at some slices in streamwise direction, the values don't seem to be realistic and it feels like the flow is passing through some filters. Interestingly, when I plotted the mesh together with the variables, the vertical noise lines happened to be at the edge between adjacent elements, which is particularly clear in lambda2 plot. Same behaviour was also found in 2D pressure plots and in turbulent channel flow cases. Has anyone observed similar things before in visualisation? I used both Paraview and VisIt for visualisation and the same thing was observed, so it shouldn't be a problem of software. In this case, I'm just wondering why the result is like this or is it because I set something wrong in my simulations? Any comments will be appreciated and thank you very much in advance. Best regards, Tony -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: l2.jpg Type: image/jpeg Size: 66013 bytes Desc: l2.jpg URL: ------------------------------ _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users End of Nek5000-users Digest, Vol 70, Issue 4 ******************************************** -------------- next part -------------- A non-text attachment was scrubbed... Name: l2.jpg Type: image/jpeg Size: 66013 bytes Desc: l2.jpg URL: From nek5000-users at lists.mcs.anl.gov Wed Dec 10 11:34:21 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Wed, 10 Dec 2014 17:34:21 +0000 Subject: [Nek5000-users] Unrealistic values at element edges In-Reply-To: References: , Message-ID: Tony, The wiggles in the quantities your plotting are generally indicative of marginal resolution for the given Reynolds number. They will go away with increased resolution. Lambda2 is not continuous a priori, but converges to a continuous function with increased resolution (exponentially fast). Are you using PnPn or PnPn-2 ? Pressure will generally look better with PnPn (and be better, in the marginally resolved, i.e., LES, case). For lambda2 it might be possible to do some filtering to get a smoother plot...(same for other quantities). I would suggest going that route --- there are several filtering strategies but I'm not certain which would be best for your particular case. You might start with the g_filter() routine in navier5.f with a diagonal scaling of the wavenumbers like: ( 1 1 1 1 1 ... 1 .99 .95 .90 ) say... which reduces the energy in the top 3 modes. There is also filter_d2() that you can experiment with. Paul ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] Sent: Wednesday, December 10, 2014 10:28 AM To: nek5000-users at lists.mcs.anl.gov Subject: Re: [Nek5000-users] Unrealistic values at element edges Dear Neks, Sorry that the image wasn't shown. I've attached it here. Hope someone can help. Thanks and regards, Tony ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov on behalf of nek5000-users-request at lists.mcs.anl.gov Sent: 10 December 2014 16:23 To: nek5000-users at lists.mcs.anl.gov Subject: Nek5000-users Digest, Vol 70, Issue 4 Send Nek5000-users mailing list submissions to nek5000-users at 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 at lists.mcs.anl.gov You can reach the person managing the list at nek5000-users-owner at 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. Unrealistic values at element edges (nek5000-users at lists.mcs.anl.gov) ---------------------------------------------------------------------- Message: 1 Date: Wed, 10 Dec 2014 16:23:02 +0000 From: nek5000-users at lists.mcs.anl.gov To: "nek5000-users at lists.mcs.anl.gov" Subject: [Nek5000-users] Unrealistic values at element edges Message-ID: Content-Type: text/plain; charset="iso-8859-1" Dear Neks, I've been running turbulent channel and pipe flows using nek5000 for a while. However, recently when I created movies of lambda2 structures and pressure iso-surfaces in channel and pipe flows I observed some "strange" values at the edge between elements. [cid:cec5092f-41be-4ae9-a468-a5fa9ab9f7ff] This is lambda2 structures in turbulent pipe flow. It is clearly visible from the picture that at some slices in streamwise direction, the values don't seem to be realistic and it feels like the flow is passing through some filters. Interestingly, when I plotted the mesh together with the variables, the vertical noise lines happened to be at the edge between adjacent elements, which is particularly clear in lambda2 plot. Same behaviour was also found in 2D pressure plots and in turbulent channel flow cases. Has anyone observed similar things before in visualisation? I used both Paraview and VisIt for visualisation and the same thing was observed, so it shouldn't be a problem of software. In this case, I'm just wondering why the result is like this or is it because I set something wrong in my simulations? Any comments will be appreciated and thank you very much in advance. Best regards, Tony -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: l2.jpg Type: image/jpeg Size: 66013 bytes Desc: l2.jpg URL: ------------------------------ _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users End of Nek5000-users Digest, Vol 70, Issue 4 ******************************************** From nek5000-users at lists.mcs.anl.gov Wed Dec 10 13:50:01 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Wed, 10 Dec 2014 19:50:01 +0000 Subject: [Nek5000-users] Unrealistic values at element edges In-Reply-To: References: Message-ID: Hi Paul, Thank you very much for your reply. I'm doing DNS of turbulent pipe flow and the plots were from a pipe flow with Re_D=5300 (Re_tau=180). Basically, I used the same grid resolution as specified in the paper "Direct numerical simulation of turbulent pipe flow at moderately high Reynolds numbers" which I think should be reasonably good for the given low Reynolds number. And I'm also using PnPn-2, the same as used in the papers which use nek5000. In this case, shall I use even better grid resolution for this Reynolds number in order to get rid of the wiggles? For Lambda2, I'll have a look at the filtering subroutines you suggested. Best regards, Tony ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov on behalf of nek5000-users-request at lists.mcs.anl.gov Sent: 10 December 2014 18:00 To: nek5000-users at lists.mcs.anl.gov Subject: Nek5000-users Digest, Vol 70, Issue 6 Send Nek5000-users mailing list submissions to nek5000-users at 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 at lists.mcs.anl.gov You can reach the person managing the list at nek5000-users-owner at 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. Re: Unrealistic values at element edges (nek5000-users at lists.mcs.anl.gov) ---------------------------------------------------------------------- Message: 1 Date: Wed, 10 Dec 2014 17:34:21 +0000 From: nek5000-users at lists.mcs.anl.gov To: "nek5000-users at lists.mcs.anl.gov" Subject: Re: [Nek5000-users] Unrealistic values at element edges Message-ID: Content-Type: text/plain; charset="us-ascii" Tony, The wiggles in the quantities your plotting are generally indicative of marginal resolution for the given Reynolds number. They will go away with increased resolution. Lambda2 is not continuous a priori, but converges to a continuous function with increased resolution (exponentially fast). Are you using PnPn or PnPn-2 ? Pressure will generally look better with PnPn (and be better, in the marginally resolved, i.e., LES, case). For lambda2 it might be possible to do some filtering to get a smoother plot...(same for other quantities). I would suggest going that route --- there are several filtering strategies but I'm not certain which would be best for your particular case. You might start with the g_filter() routine in navier5.f with a diagonal scaling of the wavenumbers like: ( 1 1 1 1 1 ... 1 .99 .95 .90 ) say... which reduces the energy in the top 3 modes. There is also filter_d2() that you can experiment with. Paul ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] Sent: Wednesday, December 10, 2014 10:28 AM To: nek5000-users at lists.mcs.anl.gov Subject: Re: [Nek5000-users] Unrealistic values at element edges Dear Neks, Sorry that the image wasn't shown. I've attached it here. Hope someone can help. Thanks and regards, Tony ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov on behalf of nek5000-users-request at lists.mcs.anl.gov Sent: 10 December 2014 16:23 To: nek5000-users at lists.mcs.anl.gov Subject: Nek5000-users Digest, Vol 70, Issue 4 Send Nek5000-users mailing list submissions to nek5000-users at 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 at lists.mcs.anl.gov You can reach the person managing the list at nek5000-users-owner at 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. Unrealistic values at element edges (nek5000-users at lists.mcs.anl.gov) ---------------------------------------------------------------------- Message: 1 Date: Wed, 10 Dec 2014 16:23:02 +0000 From: nek5000-users at lists.mcs.anl.gov To: "nek5000-users at lists.mcs.anl.gov" Subject: [Nek5000-users] Unrealistic values at element edges Message-ID: Content-Type: text/plain; charset="iso-8859-1" Dear Neks, I've been running turbulent channel and pipe flows using nek5000 for a while. However, recently when I created movies of lambda2 structures and pressure iso-surfaces in channel and pipe flows I observed some "strange" values at the edge between elements. [cid:cec5092f-41be-4ae9-a468-a5fa9ab9f7ff] This is lambda2 structures in turbulent pipe flow. It is clearly visible from the picture that at some slices in streamwise direction, the values don't seem to be realistic and it feels like the flow is passing through some filters. Interestingly, when I plotted the mesh together with the variables, the vertical noise lines happened to be at the edge between adjacent elements, which is particularly clear in lambda2 plot. Same behaviour was also found in 2D pressure plots and in turbulent channel flow cases. Has anyone observed similar things before in visualisation? I used both Paraview and VisIt for visualisation and the same thing was observed, so it shouldn't be a problem of software. In this case, I'm just wondering why the result is like this or is it because I set something wrong in my simulations? Any comments will be appreciated and thank you very much in advance. Best regards, Tony -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: l2.jpg Type: image/jpeg Size: 66013 bytes Desc: l2.jpg URL: ------------------------------ _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users End of Nek5000-users Digest, Vol 70, Issue 4 ******************************************** ------------------------------ _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users End of Nek5000-users Digest, Vol 70, Issue 6 ******************************************** From nek5000-users at lists.mcs.anl.gov Thu Dec 11 06:37:04 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Thu, 11 Dec 2014 12:37:04 +0000 Subject: [Nek5000-users] USERVP Message-ID: Hi all, I am quite new in Nek5000 and I still trying to develop the understanding to use this program. May i know what are udiff and utrans stands for in uservp subroutine in .usr file? I aware that both will be using to control the variable properties. But which parameter are those control in the equation? Thanks Muhsin -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Thu Dec 11 08:42:13 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Thu, 11 Dec 2014 14:42:13 +0000 Subject: [Nek5000-users] USERVP In-Reply-To: References: Message-ID: Hi Muhsin, For variable transport properties case (IFUSERVP=T), utrans and udiff are the transport and diffusion coefficients, respectively, in a particular advection-diffusion equation. Namely, when solving for momentum (ifield=1), they are density and dynamic viscosity, while are thermal conductivity per volume and thermal conductivity while solving for temperature (ifield=2). Note for the constant properties case, they are taken from .rea file as RHO, VISC, RHOCP and CONDUCT parameters. Aleks ________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] Sent: Thursday, December 11, 2014 6:37 AM To: nek5000-users at lists.mcs.anl.gov Subject: [Nek5000-users] USERVP Hi all, I am quite new in Nek5000 and I still trying to develop the understanding to use this program. May i know what are udiff and utrans stands for in uservp subroutine in .usr file? I aware that both will be using to control the variable properties. But which parameter are those control in the equation? Thanks Muhsin -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Wed Dec 17 08:11:14 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Wed, 17 Dec 2014 15:11:14 +0100 Subject: [Nek5000-users] Forcing term in weak form Message-ID: Hi NEK's I need to add a forcing term f to the linearized momentum equation which is proportional to the divergence of the viscous stress div(grad(Ub)+grad(Ub)^T), where Ub is the base-flow. Thus, if grad(Ub)+grad(Ub)^T=c I would like to use the weak form formulation where *-c grad w* is used, instead of *div(c)*w* (w being the test functions). Is it possible? Andrea -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Thu Dec 18 06:54:40 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Thu, 18 Dec 2014 12:54:40 +0000 Subject: [Nek5000-users] VisIt error: The first time step in a Nek file must contain a mesh Message-ID: Hi all, I get error of mesh need to contain the first time step in Nek file everytime I run .nek5000 file from results of some example (turbchannel, blasius and expansion). However for the 3dbox example, I got no error to open it. I've checked the first line in the first time step file (.f00001) and have the geometry (X) in them. I also changed the logic for coordinate output to (T COORDINATES) and different param66, but still getting the same error. Perhaps even if I put the mesh output for each timestep not just in first timestep, I still getting the same error. Note that I've already set the right plugin and type file during open the .Nek5000 file. In addition, I've checked the same parameters for 3dbox example which is same with the other example rea file, plus 3dbox still gives me no error even if i not switch the coordinate output to true (F COORDINATES) I really hope that anyone who has encountered the same problem and has solved it to assist me. That would be really helpful. Regards, -- Muhsin Mohd Amin Graduate Student Department of Mechanical Engineering The University of Sheffield -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Fri Dec 19 07:34:03 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Fri, 19 Dec 2014 14:34:03 +0100 Subject: [Nek5000-users] surface integral as function of z Message-ID: Dear Nek's I am planning to calculate the surface integral at a given ' z ' position . ( z is my flow direction) I know there is a sub routine surface_int(U,A,v,e,f) to calculate the surface integral, where the elements are identified using the boundary condition. What should I do calculate the surface integral as function of z position. / i.e E= | omega^2 dx dy / s I tried to dump the data using the function interp_v(uvw,xyz,n) at a particular cross section but it is not helping much, since I need thousands of cross section data to have E as a function of z . Thanks in advance Best Regards, Kamal From nek5000-users at lists.mcs.anl.gov Fri Dec 19 08:37:50 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Fri, 19 Dec 2014 14:37:50 +0000 Subject: [Nek5000-users] surface integral as function of z In-Reply-To: References: Message-ID: Kamal, If your elements are aligned in the z direction (e.g., as would be the case if the mesh is generated via n2to3 or genbox), then you can use one of the planar averaging routines, which would produce E(z) as a result. If you planar average zm1, you'll also get Z(z) as a result and you can plot E vs Z Paul ________________________________________ From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov] Sent: Friday, December 19, 2014 7:34 AM To: nek5000-users at lists.mcs.anl.gov Subject: [Nek5000-users] surface integral as function of z Dear Nek's I am planning to calculate the surface integral at a given ' z ' position . ( z is my flow direction) I know there is a sub routine surface_int(U,A,v,e,f) to calculate the surface integral, where the elements are identified using the boundary condition. What should I do calculate the surface integral as function of z position. / i.e E= | omega^2 dx dy / s I tried to dump the data using the function interp_v(uvw,xyz,n) at a particular cross section but it is not helping much, since I need thousands of cross section data to have E as a function of z . Thanks in advance Best Regards, Kamal _______________________________________________ Nek5000-users mailing list Nek5000-users at lists.mcs.anl.gov https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users From nek5000-users at lists.mcs.anl.gov Wed Dec 24 13:17:39 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Wed, 24 Dec 2014 14:17:39 -0500 Subject: [Nek5000-users] LES-wall Message-ID: Hello all, I have a question regarding LES capability of Nek. I know that the explicit filtering introduced in Nek can be effective for velocity field to provide sort of eddy viscosity modeling. Nevertheless, there should be some form of modeling for the near wall regions, since it is almost infeasible to have DNS like resolution in such regions for problems with relatively high Reynolds number and large scale geometries. I have seen SFR assemblies example on the Nek web in which LES used, however, I am not sure if that was an LES with near-wall resolution or with near-wall modeling. So I was wondering if anyone has any experience of using Nek LES with near wall models, or kind of hybrid RANS-LES approaches. Thanks, Mohsen From nek5000-users at lists.mcs.anl.gov Wed Dec 24 22:44:01 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Thu, 25 Dec 2014 10:14:01 +0530 Subject: [Nek5000-users] LES-wall In-Reply-To: References: Message-ID: Hi Mohsen, For LES with near wall modelling, you have to develop your own script in .usr file. There are no in-built routines except eddy_visc() in turbChannel example. If you use eddy-viscosity type of near wall models in LES, you can modify the scripts and write your own eddy-viscosity routines in uservp. Thanks, Tanmoy On Thu, Dec 25, 2014 at 12:47 AM, wrote: > Hello all, > > I have a question regarding LES capability of Nek. > I know that the explicit filtering introduced in Nek can be effective for > velocity field to provide sort of eddy viscosity modeling. Nevertheless, > there should be some form of modeling for the near wall regions, since it > is almost infeasible to have DNS like resolution in such regions for > problems with relatively high Reynolds number and large scale geometries. I > have seen SFR assemblies example on the Nek web in which LES used, however, > I am not sure if that was an LES with near-wall resolution or with > near-wall modeling. > > So I was wondering if anyone has any experience of using Nek LES with near > wall models, or kind of hybrid RANS-LES approaches. > > Thanks, > Mohsen > > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Sat Dec 27 14:56:50 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Sat, 27 Dec 2014 15:56:50 -0500 Subject: [Nek5000-users] Conjugate Heat Transfer: Flow past a Heated Cylinder Message-ID: Hello, I am currently using nek5000 to simulate flow past a heated cylinder (with volumetric energy generation) and I am interested in gathering local Nusselt number (i.e. dT/dn) information at all locations on the surface of the cylinder (with Boundary ID 'W '). "n" is the normal pointing outward from the cylinder. Since I am using mulltiple processors, I am a little stumped on how to proceed. Can anyone recommend an algorithm to output this information in an ascii file (.txt or .dat)? Thank you for your help, Saumil -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Wed Dec 24 22:23:36 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Thu, 25 Dec 2014 09:53:36 +0530 Subject: [Nek5000-users] LES-wall In-Reply-To: References: Message-ID: Hi Mohsen, For LES with near wall modelling, you have to develop your own script in .usr file. There are no in-built routines except eddy_visc() in turbChannel example. If you use eddy-viscosity type of near wall models in LES, you can modify the scripts and write your own eddy-viscosity routines in uservp. Thanks, Tanmoy Best Regards, Tanmoy On Thu, Dec 25, 2014 at 12:47 AM, wrote: > Hello all, > > I have a question regarding LES capability of Nek. > I know that the explicit filtering introduced in Nek can be effective for > velocity field to provide sort of eddy viscosity modeling. Nevertheless, > there should be some form of modeling for the near wall regions, since it > is almost infeasible to have DNS like resolution in such regions for > problems with relatively high Reynolds number and large scale geometries. I > have seen SFR assemblies example on the Nek web in which LES used, however, > I am not sure if that was an LES with near-wall resolution or with > near-wall modeling. > > So I was wondering if anyone has any experience of using Nek LES with near > wall models, or kind of hybrid RANS-LES approaches. > > Thanks, > Mohsen > > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Tue Dec 30 10:07:16 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Tue, 30 Dec 2014 11:07:16 -0500 Subject: [Nek5000-users] LES-wall In-Reply-To: References: Message-ID: Thanks Tanmoy for your suggestion. You are right, for a eddy viscosity type of turbulent model, the Channel example is a good starting point (though, I think it should be considerably modified to be used in a case with a different geometry compared to a channel). But I was thinking of using sort of wall model when employing the explicit filtering of velocity field as a LES model. Thanks, Mohsen On 24-Dec-14, at 11:23 PM, wrote: > Hi Mohsen, > > For LES with near wall modelling, you have to develop your own > script in .usr file. There are no in-built routines except eddy_visc > () in turbChannel example. If you use eddy-viscosity type of near > wall models in LES, you can modify the scripts and write your own > eddy-viscosity routines in uservp. > > Thanks, > Tanmoy > > Best Regards, > Tanmoy > > On Thu, Dec 25, 2014 at 12:47 AM, > wrote: > Hello all, > > I have a question regarding LES capability of Nek. > I know that the explicit filtering introduced in Nek can be > effective for velocity field to provide sort of eddy viscosity > modeling. Nevertheless, there should be some form of modeling for > the near wall regions, since it is almost infeasible to have DNS > like resolution in such regions for problems with relatively high > Reynolds number and large scale geometries. I have seen SFR > assemblies example on the Nek web in which LES used, however, I am > not sure if that was an LES with near-wall resolution or with near- > wall modeling. > > So I was wondering if anyone has any experience of using Nek LES > with near wall models, or kind of hybrid RANS-LES approaches. > > Thanks, > Mohsen > > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users -------------- next part -------------- An HTML attachment was scrubbed... URL: From nek5000-users at lists.mcs.anl.gov Tue Dec 30 10:29:03 2014 From: nek5000-users at lists.mcs.anl.gov (nek5000-users at lists.mcs.anl.gov) Date: Tue, 30 Dec 2014 09:29:03 -0700 Subject: [Nek5000-users] LES-wall In-Reply-To: References: Message-ID: Hi Mohsen, Yes the turbChannel case is a good point to start with. However, explicit filtering as LES model only works when using wall-resolved LES. My past experience shows, to use wall-model, one must have a good eddy-viscosity model, to properly emulate wall layer physics. Explicit filtering of LES, is way too bad in preserving the wall physics. Sincerely, Tanmoy Best Regards, Tanmoy On Tue, Dec 30, 2014 at 9:07 AM, wrote: > Thanks Tanmoy for your suggestion. > > You are right, for a eddy viscosity type of turbulent model, the Channel > example is a good starting point (though, I think it should be considerably > modified to be used in a case with a different geometry compared to a > channel). But I was thinking of using sort of wall model when employing the > explicit filtering of velocity field as a LES model. > > Thanks, > Mohsen > > On 24-Dec-14, at 11:23 PM, wrote: > > Hi Mohsen, > > For LES with near wall modelling, you have to develop your own script in > .usr file. There are no in-built routines except eddy_visc() in turbChannel > example. If you use eddy-viscosity type of near wall models in LES, you > can modify the scripts and write your own eddy-viscosity routines in > uservp. > > Thanks, > Tanmoy > > Best Regards, > Tanmoy > > On Thu, Dec 25, 2014 at 12:47 AM, wrote: > >> Hello all, >> >> I have a question regarding LES capability of Nek. >> I know that the explicit filtering introduced in Nek can be effective for >> velocity field to provide sort of eddy viscosity modeling. Nevertheless, >> there should be some form of modeling for the near wall regions, since it >> is almost infeasible to have DNS like resolution in such regions for >> problems with relatively high Reynolds number and large scale geometries. I >> have seen SFR assemblies example on the Nek web in which LES used, however, >> I am not sure if that was an LES with near-wall resolution or with >> near-wall modeling. >> >> So I was wondering if anyone has any experience of using Nek LES with >> near wall models, or kind of hybrid RANS-LES approaches. >> >> Thanks, >> Mohsen >> >> >> _______________________________________________ >> Nek5000-users mailing list >> Nek5000-users at lists.mcs.anl.gov >> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users >> > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > > > > _______________________________________________ > Nek5000-users mailing list > Nek5000-users at lists.mcs.anl.gov > https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users > > -------------- next part -------------- An HTML attachment was scrubbed... URL: