[FLASH-USERS] Refinement and Derefinement Criteria

[Robert Fisher]

Hi Seyit :

   What criterion one chooses to refine an adaptive mesh depends crucially 
upon what physics one is simulating, and what scientific questions one is 
seeking to address. There is no single silver bullet here -- while it is 
clearly advisable to fully resolve all characteristic length scales 
throughout all space and time in the problem under consideration, you will 
need to critically assess the tradeoff of what additional information 
is learned with the added cost of the simulation.

   Best wishes,

   Bob

On Wed, 23 Apr 2008, Seyit Hocuk wrote:

> Hi all,
>
> First of all thanks Anshu. I have somthing to work on now. I also consider to 
> switch to FLASH3.0. However, I have another question for anybody who can 
> reply. Sorry that I ask many questions, but this should be a simple one.
>
> Flash, as I believe, refines automatically when you don't put lrefine_max 
> equal to lrefine_min. With witch criteria can I play with the refinement and 
> how can I say when to derefine. Basically I don't completely understand how 
> refinement works and the user guide is not completely transparant about this. 
> I assumed that delta_ref, delta_deref and the reference_density were exactly 
> these parameters. I initially thought that when the density "rho" (or 
> whatever parameter is set for refinement) at each block exceeds the reference 
> density by amount of delta_ref (multiplied or added?) then it refines and 
> when it is lower by an amount of delta_deref it derefines. However, changing 
> these parameters has proven to have little effect for me.
>
> Can anybody explain me how this works and what the formula's are if any?
>
> TY,
> Seyit
>
>