[FLASH-USERS] initial density and temperature distribution in laser slab

[Kavin Tangtartharakul]

Hi Ryan,

It worked like you said, and also was easy to add the velocity into the
hdf5 outputs.
I appreciate that FLASH isn't too hard to work with and looks like a very
helpful community!

Regards,
Kavin Tangtartharakul

On Thu, Jul 18, 2024 at 2:12 PM Ryan Farber <rjfarber at umich.edu> wrote:

> Hi Kavin,
>
> In your object folder (after you run setup) there should be a file called
> "FLASH.h" which shows all the variables in your simulation. You should find
> variables called VELX, VELY, VELZ.
>
> In the same way that you set the initial conditions for your density and
> temperature, you can set initial conditions for those velocity components.
>
> Best wishes,
> --------
> Ryan
>
>
> On Thu, Jul 18, 2024 at 1:22 PM Kavin Tangtartharakul <ktangtar at ucsd.edu>
> wrote:
>
>> Everything seems to be working now for defining the initial density and
>> temperature distribution!
>>
>> But now I was just thinking that an initial velocity distribution could
>> be interesting as well.  It doesn't look like LaserSlab has any
>> implementation for an initial velocity.  Is there a straightforward way to
>> do this?
>>
>> On Thu, Jul 18, 2024 at 11:07 AM Kavin Tangtartharakul <ktangtar at ucsd.edu>
>> wrote:
>>
>>> Thank you for the quick reply! I think that makes a lot of sense and I
>>> should be able to get it working looking more closely at the user guide.
>>>
>>> On Thu, Jul 18, 2024 at 11:03 AM Lee Ellison <lee at pacificfusion.com>
>>> wrote:
>>>
>>>> Glad to hear you're making progress, Kavin.
>>>>
>>>> I suggest spending some time with Chapter 3.5 in the User guide:
>>>> https://flash.rochester.edu/site/flashcode/user_support/flash_ug_devel.pdf
>>>> <https://urldefense.com/v3/__https://flash.rochester.edu/site/flashcode/user_support/flash_ug_devel.pdf__;!!Mih3wA!FORwe9VDPaoEz8MGBTWSv7pGIK9_U8Da-0mYGjEeceCCCDM9XcAx29tbIQUWlOLus0rvPUYzJbcYZte0$>
>>>>
>>>> It has some good discussion on this initBlock routine.
>>>>
>>>> The behaviour you're seeing is because the FLASH simulation domain is
>>>> decomposed into blocks, so the index scan you're performing on lines 122
>>>> and 123 are not with respect to global index space but instead a
>>>> block-specific index space, so you're seeing per-block behavior. Instead
>>>> you'll want to do something like fetch the spatial position from the Grid
>>>> unit (again, see the User guide for instructions on this) and use the
>>>> spatial position instead of the logical index within the block.
>>>>
>>>> Best of luck!
>>>> Leland
>>>>
>>>> On Thu, Jul 18, 2024 at 10:56 AM Kavin Tangtartharakul <
>>>> ktangtar at ucsd.edu> wrote:
>>>>
>>>>> Hi Leland,
>>>>>
>>>>> Thank you for pointing me in the right direction!
>>>>> I gave it a try and there seems to be some strange behavior with the
>>>>> density. Below, I set some arbitrary functions for the density and electron
>>>>> temperature.  It seems like the initial temperature distribution is as
>>>>> expected but the density does something unexpected.  The density only
>>>>> worked when I had a constant value for it.
>>>>> [image: image.png]
>>>>>
>>>>> Below are what the initial temperature and density look like.  Any
>>>>> idea what is causing this behavior in the density?
>>>>>
>>>>> Thank you,
>>>>> Kavin Tangtartharkaul
>>>>>
>>>>> [image: image.png]
>>>>> [image: image.png]
>>>>>
>>>>> On Wed, Jul 17, 2024 at 4:07 PM Lee Ellison <lee at pacificfusion.com>
>>>>> wrote:
>>>>>
>>>>>> Hi Kavin,
>>>>>>
>>>>>> Take a look at Simulation_initBlock.F90. This is the Fortran routine
>>>>>> that specifies the initial condition for the problem. Take a look around
>>>>>> line ~100 for the body of a loop over the mesh that is specifying the
>>>>>> initial state.  You can modify this to put in whatever spatial dependence
>>>>>> you like.
>>>>>>
>>>>>> Best of luck!
>>>>>> Lee
>>>>>> ________________
>>>>>> Leland Ellison PhD
>>>>>> Pacific Fusion
>>>>>> Lead - Modeling and Simulations
>>>>>>
>>>>>> On Wed, Jul 17, 2024 at 3:41 PM Kavin Tangtartharakul <
>>>>>> ktangtar at ucsd.edu> wrote:
>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I am a new user of flash and have started working with the LaserSlab
>>>>>>> example.  Instead of just a single value fo the initial density or
>>>>>>> temperature, how can I specify the density or temperature as a function of
>>>>>>> position? For example, density = dens_base + alpha*y.
>>>>>>>
>>>>>>> Thank you,
>>>>>>> Kavin Tangtartharakul
>>>>>>> _______________________________________________
>>>>>>> flash-users mailing list
>>>>>>> flash-users at flash.rochester.edu
>>>>>>>
>>>>>>> For list info, including unsubscribe:
>>>>>>> https://flash.rochester.edu/mailman/listinfo/flash-users
>>>>>>> <https://urldefense.com/v3/__https://flash.rochester.edu/mailman/listinfo/flash-users__;!!Mih3wA!Aqb0vfk9M3B416iUVrW42YV47lVYdW5wVJpsrGtSbEFjCcviDpGkwiJctECVH93mvl1xR07fkREOYpDB$>
>>>>>>>
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>
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