[Nek5000-users] Low Mach Number solver

Tue Aug 10 15:27:06 CDT 2010

Hi Pradeep,

you'll find all details about the implemented Low Mach number algorithm in:

A.G. Tomboulides, J.C.Y. Lee, and S.A. Orzag. Numerical Simulation of Low Mach Number Reactive Flows. Journal of Scientific Computing, 1997:139–167, 12.

Only the thermodynamic pressure (p0) matters for the thermodynamic properties (e.g. density).
p0 is constant in space, in fact the current implementation makes the assumption that p0 is constant (open system).

Please note that the prenek is quite outdated and does not support all new features (e.g. Low Mach number formulation). We're working on more power meshing options which will replace prenek at some point.

hth,
Stefan

On Aug 10, 2010, at 5:50 PM, <nek5000-users at lists.mcs.anl.gov> wrote:

> Hi,
> 
> I am new to Nek5000, and had a question regarding the Low Mach Number solver.
> 
> Does the Low Mach Number solver use an algorithm that splits pressure into a time dependent, but spatially independent component ( P_thermodynamic, used to calculate the density), and a spatially and time dependent component? 
> If so, what is the variable name for P_thermodynamic?
> 
> If you use another algorithm, could you please point me to a paper that explains it (if there is one). (The examples doc from the Nek5000 wiki currently doesn't have this info.)
> 
> I am asking this to be able to correctly set/calculate rho*cp (UTRANS) in the uservp subroutine. 
> 
> Also, I am not directly able to enable the IFLOMACH option using prenek. (I need to change it manually in the .rea file by replacing the existing parameters with the ones from the lowMach_test example). I am currently using the version 2.6099999 of Nekton and the version of prenek that came with that. Is this something that will be implemented later?
> 
> Thanks,
> Pradeep
> 
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