Astronomy research
  Software Infrastructure:
     My codes
  White dwarf supernova:
     Colliding white dwarfs
     Merging white dwarfs
     Ignition conditions
     Metallicity effects
     Central density effects
     Detonation density effects
     Tracer particle burning
     Subsonic burning fronts
     Supersonic burning fronts
     W7 profiles
  Massive star supernova:
     Rotating progenitors
     3D evolution
     26Al & 60Fe
     44Ti, 60Co & 56Ni
     Yields of radionuclides
     Effects of 12C +12C
     SN 1987A light curve
     Constraints on Ni/Fe ratios
     An r-process
     Compact object IMF
     Pre-SN variations
     MC white dwarfs
     Classical novae
     He shell convection
     Presolar grains
     He burn on neutron stars
     BBFH at 40 years
  Chemical Evolution:
     Hypatia catalog
     Zone models H to Zn
     Mixing ejecta
     γ-rays within 100 Mpc
  Thermodynamics & Networks
     Stellar EOS
     Reaction networks
     Proton-rich NSE
     MC reaction rates
  Verification Problems:
     Validating an astro code
Software instruments
Bicycle adventures

AAS Journals
2017 MESA Marketplace
2017 MESA Summer School
2017 ASU+EdX AST111x
Teaching materials
Education and Public Outreach

Contact: F.X.Timmes
my one page vitae,
full vitae,
research statement, and
teaching statement.
A Comparison of High-Resolution 3D Numerical Simulations of Turbulent Rayleigh-Taylor (RT) Instability: Alpha-Group Collaboration

In this paper, the turbulent Rayleighba variety of high-resolution, multimode, three dimensional numerical simulations (NS). The perturbations are initialized with only short wavelength modes so that the self-similar evolution i.e., bubble diameter Db ∝ amplitude hb) occurs solely by the nonlinear coupling merger of saturated modes. After an initial transient, it is found that hb ∼ α A g t2 , where A=Atwood number, g=acceleration, and t=time. The NS yield Db ∼ hb/3 in agreement with experiment but the simulation value αb ∼ 0.025 ± 0.003 is smaller than the experimental value αb ∼ 0.057 ± 0.008. By analyzing the dominant bubbles, it is found that the small value of αb can be attributed to a density dilution due to fine-scale mixing in our NS without interface reconstruction (IR) or an equivalent entrainment in our NS with IR. This may be characteristic of the mode coupling limit studied here and the associated αb may represent a lower bound that is insensitive to the initial amplitude. Larger values of αb can be obtained in the presence of additional long wavelength perturbations and this may be more characteristic of experiments. Here, the simulation data are also analyzed in terms of bubble dynamics, energy balance and the density fluctuation spectra.

Simulation vs Experiment