[FLASH-USERS] resolving small scales on a large domain

[Roman Yurchak]

Hi Mario,

I think you must be missing the the lrefine_min_init parameter in your
flash.par that sets the minimum number of refinement levels at init time.

For instance with nxb==nxy==16, to resolve a 0.27um perturbation, I
assume you would want at least
lrefine_max = 8 # with max resolution  300./(16*(2**(8-1)) = 0.146 µm
then you would have to set
lrefine_min_init = 2  # i.e. 9.375 µm, as with a default value of 1
(=18.75µm) you are on the limit of detecting the foil at init time.

Besides, it is advised to have square simulations cells, that can be
achieved for a 300 um X 1200 um domain with
nblockx = 1
nblocky = 4

Best,
-- 
Roman Yurchak
PhD student
Laboratoire LULI
Ecole Polytechnique, France


On 15/09/14 23:49, Mario Manuel wrote:
> Hi,
> 
> I am trying to setup a simulation that looks at RT growth of seeded
> perturbations on a laser-accelerated foil. The foil parameters I'd like
> to implement is a 21um thick foil with a 0.27um sinusoidal amplitude
> perturbation on it. I have altered the LaserSlab simulation initBlock to
> do this and I can successfully create a 21um thick foil with a 2um
> perturbation, but as I try to make the perturbation smaller, the foil
> entirely disappears from the domain. I have tried to change the
> lrefine_max parameter to get the resolution I need, but have been thus
> far unsuccessful at getting down to the sub micron level that i need to
> run the simulation. I also ran the ./setup with nxb=32 and nyb=32 to try
> to get at the problem, but still to no avail.
> 
> The domain is rather large, 300 um X 1100 um, due to the fact that I
> need to have some computational space given to the laser-plasma
> interaction and to allow the foil to accelerate and move during the
> simulation.
> 
> Any thoughts on how I could better implement my problem?
> 
> Cheers,
> Mario 
> 
> ______________________________________
>                                                                        
>                                                         
> Dr. Mario Manuel
> Einstein Postdoctoral Fellow, Smithsonian Astrophysical Observatory
> mmanuel at umich.edu <mailto:mmanuel at umich.edu>
> 617-899-8381
> 
> University of Michigan
> Space Research Building
> 2455 Hayward Street
> Ann Arbor, MI 48109
> Office: 734-764-4585
> ______________________________________
> 


-- 
Roman