[FLASH-USERS] Problem at refinement region boundary

[dongwook at flash.uchicago.edu]

Hi Markus,

I have a look at the plots and they all seem to show some artifacts, even
for the result with the  Flash3.1 USM. In order to understand your problem
better, I'd like to ask you to send the following information to Klaus and
me:

(1) your setup line, and
(2) log files and par files for all four runs you mentioned in your last
email.

In the meantime, I'd like to suggest you perform the following tests:

(a) setup the four runs with uniform grid and see what happens, especially
check if
    (a)-1: you don't see the block-boundary artifacts in the four
different cases,
    (a)-2: you get similar density and temperature profiles for the four
different cases,
(b) setup the problem again without using your customized refinement routine,
(c) use the unsplit hydro solver not the unsplit staggered mesh solver in
FLASH4.0.

One last thing I'd like to ask you is that where did you get the private
3D version of FLASH3.1.1?

You can send log files and setup information to Klaus and myself without
sending them to the whole flash community.

Thanks,
Dongwook

> Hi,
>
> I did some more testing regarding the artifacts at the refinement
> boundary. The problem is also present in FLASH 4.0. I used exactly the
> same simulation setup and the same parameter file and made 4 runs using
> different versions of FLASH and different solvers for comparison.
>
> The initial conditions are at z=50 and I took the output after 20 time
> steps in the PPM and after 40 time steps in the USM, which corresponds
> to ~ z=20.8. The initial conditions are a uniform temperature and a
> rather smooth density field, box size is 20Mpc/h.
>
> Here is how the density distribution looks like (there are hardly any
> noticeable differences between the runs):
> http://ubuntuone.com/29SQg5m3kCnm9zkOV6KJzX
>
> Here is how a temperature slice through the center of the domain looks
> in the different runs:
>
> Flash 4 using the PPM solver:
> http://ubuntuone.com/0NC31EMXM83dXyrDsyZPDR
>
> Flash 4 using the unsplit staggerd mesh solver:
> http://ubuntuone.com/0MTUuVcnpATZN7CdU3C12E
>
> Flash3.1 with some patches using the PPM solver:
> http://ubuntuone.com/2cuKPf0wMrahLeqSiVZjzV
>
> Flash3.1 using the then private 3D version of the unsplit staggered mesh
> solver by Dongwook Lee:
> http://ubuntuone.com/05gixjehhhTOKeYRTcj5sB
>
> I should note that the artifacts increase with time. They are hardly
> noticeable in the first few time steps and become more and more
> prominent with time.
>
> As you see, this raises some questions.
>
> - All the solvers show artifacts at the refinement boundaries, except
> Flash3.1 using the 3D USM solver.
> - There is a big discrepancy in temperature between between the USM and
> the PPM solver in Flash 4.
> - The Flash3.1 USM mean temperature at z=20 is more than 5 times lower
> (13111K) compared to the USM solver in Flash 4 (74392K).
>
> Let me know if I can do more tests which could explain these differences.
>
> Thank you for your help,
> Cheers,
> Markus
>
>
>