search

Aladinux / bsim-bccs

Automatically exported from code.google.com/p/bsim-bccs
0 stars 0 forks source link

BSimChemicalField diffusivity #6

Open GoogleCodeExporter opened 8 years ago

GoogleCodeExporter commented 8 years ago 
A very high diffusivity constant gives numerical instabilities.
I've tried 800.0 and this works fine. Plugging in anything > 1000.0 returns NaN 
when exporting data.

Original issue reported on code.google.com by petros.m...@gmail.com on 2 Mar 2011 at 4:37

GoogleCodeExporter commented 8 years ago 
Have you tried increasing the grid resolution and decreasing the time-step 
size? I know this slows the simulation down but it might be the only way round 
the problem for the type of solver we have implemented at the moment. The type 
of finite difference scheme that is implemented is, I think, conditionally 
stable - the stability of the scheme is only guaranteed under certain 
conditions. I can remember for sure that in the case of 1-D PDEs this scheme's 
stability is dependent on time-step, spatial discretisation and diffusion rate 
so it is quite likely that this is also the case in 3-D.

Original comment by antmatyj...@gmail.com on 14 Mar 2011 at 2:53