<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Times New Roman; font-size: 12pt; color: #000000'>Hi Paul,<br><br>Thanks for the emails. At present, it seems easier and more straight forward to use a discriminator for RBC so long as it doesn't effect any other routine (like you mentioned other routines that use 'v '). I think, but could be wrong, that the recycling routine negates using the 'v ' boundary condition for that particular inlet? <br><br>I think that as long as the discriminator change doesn't effect anything and at the same time, not calling it 'v ' doesn't cause any issues that the discriminator would be easier. <br><br>In the mean time I can try creating the bc() based on cbc and geometry location and use that. <br><br>- Michael<br><br><br>----- Original Message -----<br>From: nek5000-users@lists.mcs.anl.gov<br>To: nek5000-users@lists.mcs.anl.gov<br>Sent: Friday, July 16, 2010 5:32:17 PM GMT -06:00 US/Canada Central<br>Subject: Re: [Nek5000-users] New Recycling BC based on interpolation<br><br><br>Hi Michael,<br><br>As a follow-up --- if you need me to code up a more sophisticated<br>discriminator, I'm happy to do so.<br><br>Paul<br><br><br>On Fri, 16 Jul 2010, nek5000-users@lists.mcs.anl.gov wrote:<br><br>><br>><br>> Hi Michael,<br>><br>> Thanks for the suggestion --- I think it's a good one, but we're<br>> not quite there yet. I have a couple of comments -<br>><br>> Technically "R " is the same as "v " --- because it is a time-space<br>> varying prescribed Dirichlet condition.<br>><br>> Why not simply populate bc(4,f,e,1) with 1,2,3,... to indicate that it is a <br>> Recycle bc of type 1,2,3,... ? For every cbc, there<br>> are 6 bc() entries (i.e, bc(k,f,e,1) for k=1 to 6). For "v ", the first one <br>> of these (k=1) is reserved.<br>><br>> That being said, genmap doesn't care about any bc other than "O " and<br>> "P " (in fact, only "P " at this point), so you could in fact do what<br>> you propose right now, as long as you replace in usrdat or usrdat2 with<br>> the functionally correct "v " bc.<br>><br>> At present I'm a bit reluctant to make a change to the repo that is<br>> still in flux w.r.t. development -- There are a few issues to resolve.<br>> Presumably what one wants to be able to specify is the translation<br>> distance -- with respect to what? -- and the scale factor as a function<br>> of time. We have selected w.r.t. to the unit normal on the R face. In<br>> exact arithmetic there's no difficulty - but in some tricky situations<br>> there will be problems. Rather than try to engineer a solution for all<br>> possible scenarios I think it's best to handle this on a case-by-case<br>> basis until we get a handle on what works and what doesn't.<br>><br>> There are also performance issues to be investigated, particularly at<br>> high processor counts.<br>><br>> In a few months I expect we'll have a consolidated code team such<br>> that we can implement changes (at least the mechanics of them)<br>> without much difficulty. Right now (through the summer) we're<br>> a bit saturated.<br>><br>> Paul<br>><br>><br>> On Fri, 16 Jul 2010, nek5000-users@lists.mcs.anl.gov wrote:<br>><br>>> Oh ok.<br>>> <br>>> Let's say that I leave one inlet as 'v ', but then change the other<br>>> inlet to some other variable 'v1 ' or 'X ' or whatever. Would this be<br>>> ok, without interfering with other routines?<br>>> <br>>> I suppose where this discussion is heading is: What is the possibility<br>>> of adding a recycling boundary condition explicity in Nek, such that<br>>> you can apply it like any other boundary condition, say R for example.<br>>> So, in the routine you now search for this recycling flag 'R', and<br>>> then run through the setup, rescale etc...?<br>>> <br>>> -Michael<br>>> <br>>> ----- Original Message -----<br>>> From: nek5000-users@lists.mcs.anl.gov<br>>> To: nek5000-users@lists.mcs.anl.gov<br>>> Sent: Friday, July 16, 2010 4:47:11 PM GMT -06:00 US/Canada Central<br>>> Subject: Re: [Nek5000-users] New Recycling BC based on interpolation<br>>> <br>>> <br>>> Hi Michael,<br>>> <br>>> Use whatever discrimination you like --- I would not suggest<br>>> modifying the character bcs, however, save that you can enter<br>>> values in bc(k,f,e,1) for k > 1, for any cbc(f,e,1) = 'v '<br>>> <br>>> The reason for this is that nek checks explicitly for cbc='v '<br>>> (v, followed by two spaces) in many locations.<br>>> <br>>> The correct place for discriminating parameters is in the<br>>> arracy bc().<br>>> <br>>> Normally I discriminate by geometry --- e.g., x < x0, or<br>>> something similar, occasionally involving the unit normals on<br>>> the face in question - as that can be a stronger discriminator.<br>>> <br>>> Paul<br>>> <br>>> <br>>> On Fri, 16 Jul 2010, nek5000-users@lists.mcs.anl.gov wrote:<br>>> <br>>>> Hi Aleks,<br>>>> <br>>>> Thank you very much for looking into this. I already have a question; I <br>>>> noticed that you marked several notes dealing with "RBC single inlet -- <br>>>> modify for other cases". I am assuming this means that you have one inlet <br>>>> that you want to recycle, but another inlet that you do not want to <br>>>> recycle, which just happens to be my case.<br>>>> <br>>>> Can I distinguish in the rea between the two by "v1 " and "v2 " without <br>>>> giving genmap any problems, and then modify the checks in the usr file <br>>>> accordingly? Also, the subroutine rescale_inflow mentions to modify for <br>>>> multiple inlets as well but I do not see where any modification <br>>>> could/needs to be done for it.<br>>>> <br>>>> - Michael<br>>>> <br>>>> ----- Original Message -----<br>>>> From: nek5000-users@lists.mcs.anl.gov<br>>>> To: nek5000-users@lists.mcs.anl.gov<br>>>> Sent: Friday, July 16, 2010 3:03:52 PM GMT -06:00 US/Canada Central<br>>>> Subject: [Nek5000-users] New Recycling BC based on interpolation<br>>>> <br>>>> Hi Michael and Markus,<br>>>> <br>>>> Here is a test case for an unsteady pipe flow with Michael's <br>>>> GambitPipe.rea file which sets inlet Recycling BCs based on interpolation <br>>>> from a cross-section downstream that you specify by a multiple of the <br>>>> inlet normal:<br>>>> <br>>>> http://www.mcs.anl.gov/~obabko/z4.tgz<br>>>> <br>>>> <br>>>> Let me know if you have any questions.<br>>>> Best,<br>>>> Aleks<br>>>> <br>>>> <br>>>> <br>>>> <br>>>> ----- Original Message -----<br>>>> From: nek5000-users@lists.mcs.anl.gov<br>>>> To: nek5000-users@lists.mcs.anl.gov<br>>>> Sent: Thursday, July 8, 2010 5:06:48 PM GMT -06:00 US/Canada Central<br>>>> Subject: Re: [Nek5000-users] New Recycling BC method?<br>>>> <br>>>> <br>>>> <br>>>> <br>>>> <br>>>> No worries, just checkin in to see how it was going, thanks for the <br>>>> update! Look forward to trying it out!<br>>>> <br>>>> <br>>>> <br>>>> - Michael<br>>>> <br>>>> _______________________________________________<br>>>> Nek5000-users mailing list<br>>>> Nek5000-users@lists.mcs.anl.gov<br>>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users<br>>>> <br>>> _______________________________________________<br>>> Nek5000-users mailing list<br>>> Nek5000-users@lists.mcs.anl.gov<br>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users<br>>> <br>> _______________________________________________<br>> Nek5000-users mailing list<br>> Nek5000-users@lists.mcs.anl.gov<br>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users<br>><br>_______________________________________________<br>Nek5000-users mailing list<br>Nek5000-users@lists.mcs.anl.gov<br>https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users<br></div></body></html>