Direct numerical simulations of the κ-mechanism

Details Direct numerical simulations of the κ-mechanism Direct numerical simulations of the κ-mechanism

Nov 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008sf2a.conf..471g&link_type=abstract

"SF2A-2008: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics Eds.: C. Charbonnel, F. Combes

Astronomy and Astrophysics

Astrophysics

Scientific paper

We present a purely-radiative hydrodynamic model of the κ-mechanism that sustains radial oscillations in Cepheid variables. We determine the physical conditions favourable for the κ-mechanism to occur by the means of a configurable hollow in the radiative conductivity profile. By starting from these most favourable conditions, we complete nonlinear direct numerical simulations (DNS) and compare them with the results given by a linear-stability analysis of radial modes. We find that well-defined instability strips are generated by changing the location and shape of the conductivity hollow. For a given position in the layer, the hollow amplitude and width stand out as the key parameters governing the appearance of unstable modes driven by the κ-mechanism. The DNS confirm both the growth rates and structures of the linearly-unstable modes. The nonlinear saturation that arises is produced by intricate couplings between the excited fundamental mode and higher damped overtones. These couplings are measured by projecting the DNS fields onto an acoustic subspace built from regular and adjoint eigenvectors and a 2:1 resonance is found to be responsible for the saturation of the κ-mechanism instability.

Affiliated with

Also associated with

No associations

Rating

Direct numerical simulations of the κ-mechanism does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Direct numerical simulations of the κ-mechanism, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Direct numerical simulations of the κ-mechanism will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1287868