[Nek5000-users] Nek5000 and Non-Newtonian Fluids

[nek5000-users at lists.mcs.anl.gov]

Hi Mike,

Probably the best point to start is in the lambda2 routine,
to be found in postpro.f, which reads in part as:


       do ie=1,nelv
          ! Compute velocity gradient tensor
          call comp_gije(gije,vx(1,1,1,ie),vy(1,1,1,ie),vz(1,1,1,ie),ie)

          do l=1,nxyz
             ! decompose into symm. and antisymm. part
             do j=1,ndim
             do i=1,ndim
                ss(i,j) = 0.5*(gije(l,i,j)+gije(l,j,i))
                oo(i,j) = 0.5*(gije(l,i,j)-gije(l,j,i))
             enddo
             enddo

etc.

I think from their you can see how to compute what you need.
(Let me know if you have questions...)

If you get such a routine (e.g., "compute_q") and are happy
with it after a few trials, I'd be happy to insert it into the repo.

Cheers,

Paul



On Mon, 17 Jan 2011, nek5000-users at lists.mcs.anl.gov wrote:

> Paul,
>
> I switched this to the nek5000-users channel  in case we discuss some thing relevant to others.
>
> For the Bingham model, it seems that all I need is to calculate the second invariant of the strain rate tensor, which is then used to calculate the time-varying apparent viscosity.   I suspect the routine building-blocks for generating this tensor are already in the nek distribution.  If so, could you point me in that direction?
>
> Once those routines are in order, all the calculation will be directed out of uservp, correct?
>
> Thanks.
> --Mike
>
>
> On Jan 14, 2011, at 7:27 AM, Paul Fischer wrote:
>
>> Hi Mike,
>>
>> [...]
>> The "peris" case uses the stress formulation, as do the "fs"
>> cases.  These have the correct SiZE files (resp. for 3D and 2D)
>> and flags in the .rea file, save that you would set "IFMVBD"
>> to false, since you don't want moving boundaries.
>>
>> [...]
>> The code was used
>> for a lot of non-Newtonian stuff by Lee Ho and Einar, however,
>> so it has been exercised significantly in the past.
>> [...]
>
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