[FLASH-USERS] NohCylindrical problem - different results using different FLASH versions

[Loffelmann, Jiri]

Hello FLASH users,

I ran the problem magnetoHD/NohCylindrical (Magnetized Noh Z-pinch) that is provided with the code (version 4.7.1) and I got a weird result, a bit different from Figure 34.50 in the PDF guide. In this result, one can see some oscillations that are created at the top and bottom of the computational interval.
When I run the same problem with FLASH code version 4.6.2, I get the same result as is presented in the guide (Figure 34.50), without these oscillations.
When run with version 4.7, the result is the same as with version 4.7.1 (with oscillations).

>From this, I conclude that there is some kind of bug in the new versions of the code. But I have no idea what it could be...
When I increase the resolution, the frequency of the oscillations also increases.
I did not notice this in other simulations, probably when using mag. diffusion, these oscillations are negligible?

Here is a detailed description of the performed simulations:
I performed simulations using different meshes and different values of conserveAngField (no specific reason, just noticed it also does something..).
I have attached the results figures with corresponding names.
Simulations use provided .par files (some with described modifications).

version FLASH4.6.2:
1] data_4.6.2_amr
./setup -auto magnetoHD/NohCylindrical -2d +cylindrical +hdf5typeio +usm
mpirun -np 4 ./flash4
flash.par  unchanged

2] data_4.6.2_ug
./setup -auto magnetoHD/NohCylindrical -2d +cylindrical +hdf5typeio +usm +ug -nxb=128 -nyb=128
mpirun -np 4 ./flash4
flash.par  unchanged

3] data_4.6.2_ug_2
./setup -auto magnetoHD/NohCylindrical -2d +cylindrical +hdf5typeio +usm +ug -nxb=128 -nyb=128
mpirun -np 4 ./flash4
flash.par  changed: added line "conserveAndField=.true."

version FLASH4.7.1:
1] data_4.7.1_amr
./setup -auto magnetoHD/NohCylindrical -2d +cylindrical +hdf5typeio +usm
mpirun -np 4 ./flash4
flash.par  changed: added line "useMagneticResistivity=.false." (in the new version, the default was changed to .true.)

2] data_4.7.1_ug
./setup -auto magnetoHD/NohCylindrical -2d +cylindrical +hdf5typeio +usm +ug -nxb=128 -nyb=128
mpirun -np 4 ./flash4
flash.par  changed: added line "useMagneticResistivity=.false."

3] data_4.7.1_ug_2
./setup -auto magnetoHD/NohCylindrical -2d +cylindrical +hdf5typeio +usm +ug -nxb=128 -nyb=128
mpirun -np 4 ./flash4
flash.par  changed: added lines "useMagneticResistivity=.false.", "conserveAndField=.true."

Do you have any tips, on what it could be?

Regards,
Jiří Löffelmann

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20231004/f3da2037/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data_4.6.2_ug_2.png
Type: image/png
Size: 38937 bytes
Desc: data_4.6.2_ug_2.png
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20231004/f3da2037/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data_4.6.2_ug.png
Type: image/png
Size: 40665 bytes
Desc: data_4.6.2_ug.png
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20231004/f3da2037/attachment-0001.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data_4.6.2_amr.png
Type: image/png
Size: 39720 bytes
Desc: data_4.6.2_amr.png
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20231004/f3da2037/attachment-0002.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data_4.7.1_ug_2.png
Type: image/png
Size: 41606 bytes
Desc: data_4.7.1_ug_2.png
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20231004/f3da2037/attachment-0003.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data_4.7.1_ug.png
Type: image/png
Size: 38017 bytes
Desc: data_4.7.1_ug.png
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20231004/f3da2037/attachment-0004.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data_4.7.1_amr.png
Type: image/png
Size: 44484 bytes
Desc: data_4.7.1_amr.png
URL: <http://flash.rochester.edu/pipermail/flash-users/attachments/20231004/f3da2037/attachment-0005.png>