[Nek5000-users] Nek5000 and Non-Newtonian Fluids

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

Paul,

That's got what I need, thanks.

Also, are there any examples in the distribution that use the stress formulation and variable viscosity?

Thanks.
--Mike

On Jan 18, 2011, at 6:22 AM, <nek5000-users at lists.mcs.anl.gov> wrote:

> 
> 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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