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

[Kavin Tangtartharakul]

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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