AffiliationUniv Arizona, Dept Astron
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PublisherOXFORD UNIV PRESS
Citation3D hydrodynamic simulations of carbon burning in massive stars 2017, 471 (1):279 Monthly Notices of the Royal Astronomical Society
Rights© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
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AbstractWe present the first detailed 3D hydrodynamic implicit large eddy simulations of turbulent convection of carbon burning in massive stars. Simulations begin with radial profiles mapped from a carbon-burning shell within a 15M circle dot 1D stellar evolution model. We consider models with 128(3), 256(3), 512(3), and 1024(3) zones. The turbulent flow properties of these carbon-burning simulations are very similar to the oxygen-burning case. We performed a mean field analysis of the kinetic energy budgets within the Reynolds-averaged Navier-Stokes framework. For the upper convective boundary region, we find that the numerical dissipation is insensitive to resolution for linear mesh resolutions above 512 grid points. For the stiffer, more stratified lower boundary, our highest resolution model still shows signs of decreasing sub-grid dissipation suggesting it is not yet numerically converged. We find that the widths of the upper and lower boundaries are roughly 30 per cent and 10 per cent of the local pressure scaleheights, respectively. The shape of the boundaries is significantly different from those used in stellar evolution models. As in past oxygen-shell-burning simulations, we observe entrainment at both boundaries in our carbon-shell-burning simulations. In the large Peclet number regime found in the advanced phases, the entrainment rate is roughly inversely proportional to the bulk Richardson number, Ri(B) (alpha Ri(B)(-alpha) a, 0.5 less than or similar to alpha less than or similar to 1.0). We thus suggest the use of Ri(B) as a means to take into account the results of 3D hydrodynamics simulations in new 1D prescriptions of convective boundary mixing.
VersionFinal published version
SponsorsEU-FP7-ERC-St Grant ; World Premier International Research Centre Initiative (WPI Initiative), Ministry of Education, Science and Culture (MEXT), Japan; COST (European Cooperation in Science and Technology); National Science Foundation grant [OCI-1053575]; NSF at the University of Arizona ; European Research Council [341157-COCO2CASA]; BIS National E-infrastructure capital grant [ST/K00042X/1]; STFC capital grants [ST/H008519/1, ST/K00087X/1]; STFC DiRAC Operations grant [ST/K003267/1]; Durham University