[Nek5000-users] New Recycling BC method?

Sun Jun 20 13:26:28 CDT 2010

Hi Paul,

Were you able to find a solution for this?

I was able to establish a new connectivity matrix for connecting an  
arbitrary inlet plane to an outflow plane that you specifiy by a  
number of elements. This could be called once at the beginning. I'm  
not sure how to use it though but it is a positive start.

- Michael

On Jun 16, 2010, at 10:00 PM, nek5000-users at lists.mcs.anl.gov wrote:

> Sounds great!  Thanks for looking into this!
>
>
>
> - Michael
>
>
> ----- Original Message -----
> From: nek5000-users at lists.mcs.anl.gov
> To: nek5000-users at lists.mcs.anl.gov
> Sent: Wednesday, June 16, 2010 9:58:53 PM GMT -06:00 US/Canada Central
> Subject: Re: [Nek5000-users] New Recycling BC method?
>
> Michael, got it... I should be able to send a fix by morning that  
> will work for any instances in which slab at location A has same  
> (arbitrary) topology orientation as slab at location B, as is the  
> case in the example you sent. This won't cover all cases but would  
> likely cover 90%. hth, Paul On Wed, 16 Jun 2010, nek5000-users at lists.mcs.anl.gov 
>  wrote: > > > Paul, > > > > See attached for the rea. Thanks, > > >  
> > Michael > > > ----- Original Message ----- > From: nek5000-users at lists.mcs.anl.gov 
>  > To: nek5000-users at lists.mcs.anl.gov > Sent: Wednesday, June 16,  
> 2010 9:47:29 PM GMT -06:00 US/Canada Central > Subject: Re: [Nek5000- 
> users] New Recycling BC method? > > 960 is ok On Wed, 16 Jun 2010, nek5000-users at lists.mcs.anl.gov 
>  wrote: > > > Paul, > > > > The rea I have now from matlab/gambit  
> has 960 elements.  Do you want me to create another, smaller rea  
> that may make it easier to work with? > > > > The geometry by the  
> way is a simple pipe flow. > > > > - Michael > > > ----- Original  
> Message ----- > From: nek5000-users at lists.mcs.anl.gov > To: nek5000-users at lists.mcs.anl.gov 
>  > Sent: Wednesday, June 16, 2010 9:39:59 PM GMT -06:00 US/Canada  
> Central > Subject: Re: [Nek5000-users] New Recycling BC method? > >  
> Hi Micheal, I agree completely that it's best to avoid mix & match  
> meshing. If you want to send me a gzipped .rea file produced by  
> Gambit, I can take a look and see if I have any ideas. Paul On Wed,  
> 16 Jun 2010, nek5000-users at lists.mcs.anl.gov wrote: > > > Hi Paul, >  
> > > > Thanks for the reply.  The reason for the interest is due to  
> the Gambit to Nek matlab code. We have had great success importing  
> complex geometries with it, but no w we run into the issue of the  
> recycling boundary condition.  Gambit's ordering of the elements is  
> not always consistent which makes it impossible to use the current  
> technique. > > > > Our solution was to create the portion that has  
> the recycling in prex and then merge it with the complex part  
> created in Gambit. However, this is proving to be very time  
> consuming and troublesome (Element Mismatch Errors).  So, to avoid  
> this I would like to come up with a new recycling method that does  
> not depend on the elements being in a specific order. My u  
> nderstanding is that the current method looks at the inflow, counts  
> a certain number of elements up, copies this outflow from face 6 and  
> puts it back into the inflow face 5. > > > > What I would like to do  
> is replace how the inflow plane is connected to the outflow plane.  
> My idea was to use the connectivity matrix to figure out what the  
> element numbers and outflow faces are at a certain distance away  
> from the inflow plane, and use t hese faces to connect.  The cross- 
> section for the inflow and outflow plane would be the same, but you  
> couldn't necessarily say that it is located, say inflow + 30  
> elements for example, OR that the outflow and inflow faces are all  
> the same (face 5 for inflow, face 6 for outflow for example).  > > >  
> > Do you think this is possible? In a way, you would be creating a  
> new connectivity matrix that governs the recycling BC. > > > >  
> Thanks! > > - Michael M. > > > ----- Original Message ----- > From:  
> nek5000-users at lists. mcs . anl .gov > To: nek5000-use rs at lists.  
> mcs . anl .gov > Sent: Wednesday, June 16, 2010 9:08:00 PM GMT  
> -06:00 US/Canada Central > Subject: Re: [Nek5000-users] New  
> Recycling BC method? > > Hi Michael, Access to the connectivity  
> array wouldn't help in this case, given that the recycling bc needs  
> to establish a _new_ connectivity that has nothing to do with the  
> existing one. The examples use this approach of establishing a new  
> connectivity. I'm confident that we ca n make the existing approach  
> for any mesh that can legitimally employ the recycling bc - i.e.,  
> any mesh that has the same cross-sectional distribution of elements  
> at the two planes of interest. An alternative is to use the general  
> purpose interpolation routines. There may (or may not) be a  
> performance issue -- we're looking into this w/ the help of a summer  
> student. Please let me know if I can assist you w/ your specific  
> case. Paul > I am still trying to figure this idea out, but I think  
> I would need to > access the connectivity/boundary condition  
> information that is contained > in the rea file. Does anyone know  
> the array, or what to call in order to > access this in the usr  
> file?  Thanks again for a ny help! > > > > - Michael M. > > > -----  
> Original Message ----- > From: nek5000-users at lists. mcs . anl .gov >  
> To: " Nekton User List" > Sent: Tuesday, June 15, 2010 9:02:00 PM  
> GMT -06:00 US/Canada Central > Subject: [Nek5000-users] New  
> Recycling BC method? > > > > > Hello All, > > > > I am wondering if  
> there is another technique to set up a recycling boundary condition  
> that does not depend on the elements being in a certain order (say  
> based on element coordinates for instance)?   I would like to pick  
> the recycling plane based on a given offset distance rather than a  
> number of elements. > > > > Also, the outflow plane faces may not  
> all necessarily be face 6 (and face 5 for the inflow plane). > > > >  
> I have tried going through the examples where a recycling BC is used  
> however I am finding it difficult to understand as my knowledge of  
> Fortan is still growing. Thanks for any help anyone can provide with  
> this idea. > > > > Regards, > > Michael M. > > >   >  
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