[Nek5000-users] Primer for reacting flows

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

Let me make a couple of comments in addition to what I said:

Most of the plug-in features were moved into Nek some time ago. The
infrastructure is there to simulate reactive flows but the little (but
still time consuming ) details are missing. All you have to do is:

Code some routines to compute thermophysical and thermodynamic
properties. In addition you need a routine to compute the species
production term. For detailed chemistry and transport use a package
like Chemkin. In case you want to use a mixture averaged transport
model code up a routine to compute the terms related to the correction
velocitiy and add them to the energy and species equations.

That's it. Everything else is there!

I guess the difficult part is to get familiar with the internals of
Nek. Except from that it's pretty straightforward and shouldn't take
that long to implement.

Hth,
Stefan

On 7/29/11, S K <stgeke at googlemail.com> wrote:
> Mike, I don't know. Contact me off list to discuss the details.
> -Stefan
>
> On 7/29/11, nek5000-users at lists.mcs.anl.gov
> <nek5000-users at lists.mcs.anl.gov> wrote:
>> Stefan, Josh, Dave,  thanks for the responses.
>>
>> Dave -- pointing me to the shear4 example and sending the files was
>> helpful.
>>  Thanks!
>>
>> Stefan, I might be able to pull of what I need to do now with the
>> current-version passive-scalar features.  That said, coupling nek with
>> CVODE
>> is quite appealing.   Are there any plans for your reactive-flow plug-in
>> to
>> be available publicly?
>>
>> --Mike
>>
>> On Jul 29, 2011, at 9:55 AM, <nek5000-users at lists.mcs.anl.gov> wrote:
>>
>>> My thesis is probably a good point to start :)
>>> http://e-collection.library.ethz.ch/view/eth:1899
>>>
>>> -Stefan
>>>
>>> On 7/29/11, nek5000-users at lists.mcs.anl.gov
>>> <nek5000-users at lists.mcs.anl.gov> wrote:
>>>> 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
>>>>>>>
>>>>>>> _______________________________________________
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>>>>>>> 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
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