Thank you Roland,
https://arxiv.org/abs/1704.07383 is exactly what I want to repeat.
Thank you for you help, I will contact the 1st author for help of your paper if I failed.
Best Wishes.
Yours, Zhi-Chao.
2017-08-18 23:44 GMT+08:00 Roland Haas roland.haas@physics.gatech.edu:
Hello all,
Could you give more details about the physics you are trying to add? "atmosphere" in this context usually means an artificial low density fluid in a matter simulation which helps with numerical problems that occur when the density drops to zero. It doesn't make sense to add it to a BBH simulation, which is vacuum.
Do you mean that you want to add a low density fluid to a BBH simulation?
In case you are planning something similar to https://arxiv.org/abs/1704.07383 then you may want to contact the first author (Joseph Fedrow) possibly through this list (he's subscribed). Typically you will get failures of con2prim near the punctures and have to take special measures to work around it.
Usually this involves setting
- GRHydro::recon_method = ppm # since it is very robust
- GRHydro::reconstruct_Wv = yes # avoids some v^2>c^2 situations
- GRHydro::riemann_solver = "Marquina" # better than HLLE for this
- GRHydro::sqrtdet_thr = 10. # or so, these apply Joshua Faber's methods described in https://arxiv.org/abs/0708.2436
- GRhydro::c2p_resort_to_bisection = yes # try bisection if Newton-Raphson iteration fails
Note that my recollection of the paper by Fedrow (I am a co-author) was that all of those were required but not quite enough and that Christian Ott had to write a special con2prim routine that handled the BH interior carefully.
There is a also code in TwoPunctures that can solve the constraints (the TP code is in the ET but not the code that eg provides a density profile). Again best would be to contact the authors (all reachable through this list).
Yours, Roland
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