[Nek5000-users] Primer for reacting flows

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

Hi Stefan,

Reactive flows are something my group is also wanting to look at
possibly in the near future.  I know you said the plug-in is not
available, but was a paper produced from the work?  I thought it might
be interesting  (and informative) to read the paper if it exists.

Thanks,

Josh

On Fri, Jul 29, 2011 at 9:42 AM,  <nek5000-users at lists.mcs.anl.gov> wrote:
> Hi Mike,
>
> The base version of Nek is not ready to simulate chemically reacting
> flows. What are the fits and gaps?
>
> Fits:
> - Low Mach number formulation to deal with density varying flows
> - Accurate splitting formulation to segregate the hydrodynamic
> sub-system (momentum+continuity eqn) and the thermochemical sub-system
> (energy and species eqn)
> - Interface to CVODE (a high order integrator to solve the stiff
> thermochemical sub system efficiently)
>
> Gaps:
> - Routine to compute the RHS (needed input for CVODE)
> - The routine to compute the thermal divergence does not include the
> species eqns
> - Routines to compute the thermophysical and kinetic properties
>
> I developed a plug-in to do reactive DNS using Nek  when I was a PhD
> student at ETH Zurich. It performed really well and we did some pretty
> impressive simulations at the time
> (http://nek5000.mcs.anl.gov/index.php/Visualization_Gallery). I am
> afraid the plug-in is not available for the public :(
>
> Cheers,
> Stefan
>
> On 7/28/11, nek5000-users at lists.mcs.anl.gov
> <nek5000-users at lists.mcs.anl.gov> wrote:
>> Hi Mike,
>>
>> Here are the .rea and .usr files of a case I did with 2 reacting scalars.
>> The files are modified versions of the rayleigh case from repo that
>> simulates the Boussinesq equations, but I turned off the buoyancy term and
>> added a second scalar with reaction.
>>
>> In the userq routine in the .usr file, the qvol term specifies scalar
>> production due to reaction.  The first scalar is called temp.  The next ones
>> are ps(1), ps(2), etc.  The conditional statement (ifield.eq.2) specifies
>> production of temp, the (ifield.eq.3) statement specifies production of
>> ps(1).
>>
>> The README of the shear4 example from repo, which has 4 passive scalars,
>> describes how you can change the parameters relating to the multiple
>> scalars.
>>
>> hth,
>>
>> David
>>
>>
>> On Thu, Jul 28, 2011 at 2:57 PM, <nek5000-users at lists.mcs.anl.gov> wrote:
>>
>>> All,
>>>
>>> I'm interested in using Nek for simulation of reacting flows.  Can anyone
>>> send me, or point me towards, a simple example that could get me going?  I
>>> guess I'm most interested to see the details of storage/operation with
>>> passive scalars.
>>>
>>> Thanks.
>>> --Mike
>>>
>>> _______________________________________________
>>> Nek5000-users mailing list
>>> Nek5000-users at lists.mcs.anl.gov
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>>>
>>
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-- 
Josh Camp

"All that is necessary for the triumph of evil is that good men do
nothing" -- Edmund Burke