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arXiv · 1001.0487

Numerical simulations of the kappa-mechanism with convection

T. Gastine·B. Dintrans
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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.

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T. Gastine, B. Dintrans. 2010-01-05. Numerical simulations of the kappa-mechanism with convection. https://doi.org/10.1007/s10509-010-0276-3

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