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

[Ryan Farber]

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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