[Users] Problems with regridding?

[Ian Hinder]

On 2 Mar 2016, at 18:19, Geraint Pratten <g.pratten at sussex.ac.uk> wrote:

> Hi,
> 
> So I've tried to change a few things to see if there was an obvious solution and there does not seem to be any improvement at all. I've added a Carpet::poison_value of 100 to the .par file. I have also tried using various different grid structures (including the ​example structure used in the /par/arxiv/bbh folders - though adapted to 3D without symmetry).​ The errors ​always seem to occur around 75-85M irrespective of the grid structure though. I really am baffled as to what could be causing this problem. 

Hi Geraint,

Would it be possible to see the whole parameter file?  What dissipation are you using?  It might be too high.  I now use a maximum of 0.15 for a Courant factor of 0.45, and 0.075 for a Courant factor of 0.225, as you have on RL0.  I found that with sixth order differencing, anything higher than that eventually led to instabilities, especially with multipatch.  Also, what order of finite differencing are you using, and what value of the gamma-driver eta parameter? It might not be anything directly related to regridding at all.

-- 
Ian Hinder
http://members.aei.mpg.de/ianhin

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