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Numerical simulations of the kappa-mechanism with convection

Authors :
Gastine, T.
Dintrans, B.
Publication Year :
2010

Abstract

A strong coupling between convection and pulsations is known to play a major role in the disappearance of unstable modes close to the red edge of the classical Cepheid instability strip. As mean-field models of time-dependent convection rely on weakly-constrained parameters, we tackle this problem by the means of 2-D Direct Numerical Simulations (DNS) of kappa-mechanism with convection. Using a linear stability analysis, we first determine the physical conditions favourable to the kappa-mechanism to occur inside a purely-radiative layer. Both the instability strips and the nonlinear saturation of unstable modes are then confirmed by the corresponding DNS. We next present the new simulations with convection, where a convective zone and the driving region overlap. The coupling between the convective motions and acoustic modes is then addressed by using projections onto an acoustic subspace.<br />Comment: 5 pages, 6 figures, accepted for publication in Astrophysics and Space Science, HELAS workshop (Rome june 2009)

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.1001.0487
Document Type :
Working Paper
Full Text :
https://doi.org/10.1007/s10509-010-0276-3