2010/01/05 by T. Gastine, B. Dintrans · 2 citations
Computer Science · Engineering · Physics and Astronomy · #Combustion and flame dynamics #Convection #Convection zone #Convective instability #Coupling (piping) #Fluid Dynamics and Turbulent Flows #Instability #Instability strip #Nonlinear Dynamics and Pattern Formation #Nonlinear system #Stability (learning theory) #astro-ph.SR
paper · pdf · doi:10.1007/s10509-010-0276-3
published in Astrophysics and Space Science 328(1-2), 245-251 (Springer Science+Business Media) · 5 pages, 6 figures, accepted for publication in Astrophysics and Space Science, HELAS workshop (Rome june 2009)
arxiv created 2010/01/05 · openalex publication_date 2010/01/28 · arxiv updated 2015/05/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.