[FLASH-USERS] Sedov Units

[Marissa Adams]

I am also wondering if there is some sort of error check in the code, or
something that can keep track of energy conservation?

On Tue, Jun 28, 2016 at 8:30 AM, Marissa Adams <madams15 at ur.rochester.edu>
wrote:

> Hi Klaus,
>
> Thank you for the quick response.
>
> On Mon, Jun 27, 2016 at 4:32 PM, Klaus Weide <klaus at flash.uchicago.edu>
> wrote:
>
>> On Mon, 27 Jun 2016, Marissa Adams wrote:
>>
>> > Sorry to be a bother. I'm the only person in my group using FLASH. I'm
>> not
>> > even sure after reading the documentation, but any chance you can
>> quickly
>> > inform me, or verify the Sedov problem units/order of mag. are CGS,
>> i.e.:
>> >
>> > sim_pAmbient; 1 dyn*cm^-2
>> > sim_rhoAmbient; 1 dyn*cm^-2
>> > sim_expEnergy;  1 erg
>> > sim_rInit; 1 cm
>> > sim_*ctr; 1 cm
>> >
>> > ​Thanks, I really appreciate it. In the discussion of the problem in the
>> > documentation, parameters aren't written with units. I want to make
>> sure I
>> > have this right.
>>
>> Marissa,
>>
>> The physical units for those runtime parameters are as you assume,
>> since those are the usual cgs-system units;
>> except for sim_rhoAmbient, which should be g*cm^-3.
>>
>> (Or, to make a more cautious statement: the units you give above are a
>> reasonable interpretation, indeed the canonical one when runtime parameter
>> pc_unitsBase has not been set to "MKS". ["MKS" has not been properly
>> tested and I would not recommend trusting it.]
>> The point of this qualification is: one might interpret those values as
>> being in some other set of units - some people like "dimensionless" units
>> - and establish a different mapping to real physical units.)
>>
>> As another caveat, I am not convinced that the initialization of the
>> Sedov problem in terms of the total absolute energy is correct;
>> at least I have heard someone claim in the past that it was wrong by some
>> factor; but maybe that applies only to 1D or 2D cases.
>>
>
> ​I've been running 2d cylindrical sedov simulations with the explosion
> happening at the bottom of the grid with reflective boundary conditions for
> a 1x4 box. I'm trying to study instabilities, progressing toward a HEDP
> scheme.
>
> I'm fine with using CGS units, just wanted to make sure my conversion was
> right. Thank you again for responding so fast!
>
> Moving forward I have a few more questions/asking for advice:
>
> ​1. In the documentation there is mention of the Sedov problem with walls.
> I am interested in running this problem and changing the position of the
> walls. Am I correct that the problem module for that is in
> */FLASH4.3/source/Simulation/SimulationMain/SedovSolidWall* ? I've tried
> running this problem. It makes, but when running the executable the job
> immediately fails. I haven't thoroughly investigated why, but I am
> wondering if I need any particular module or library loaded other than
> HDF5, openmpi, intel etc. I also have HYPRE path in my Makefile.h too..
> just wondering.
>
> 2. Now say I get a sedov problem with walls made and running. I eventually
> want to make this problem multimaterial with Eos tables with HEDP units. Do
> you have any advice on how to make a problem multimaterial in FLASH?
>
>
>>
>> Btw. in general I would prefer questions to the mailing list; that way,
>> more people may be able to help, and answers can be helpful to more
>> people.
>>
>
> ​No problem. Sorry about that :)​
>
>
>
>>
>>
>>
>> Klaus
>
>
>
>
​Also my e-mail bounced back from the user list, but this one should work.​



>
> --
> Marissa Adams                         E-mail: madams at pas.rochester.edu
> Graduate Student                      Ph: (585) 402-5779
> Department of Physics & Astronomy     Website:
> http://www.pas.rochester.edu/~madams/
> University of Rochester
> 478 Bausch & Lomb Hall
> P.O. Box 270171
>



-- 
Marissa Adams                         E-mail: madams at pas.rochester.edu
Graduate Student                      Ph: (585) 402-5779
Department of Physics & Astronomy     Website:
http://www.pas.rochester.edu/~madams/
University of Rochester
478 Bausch & Lomb Hall
P.O. Box 270171
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