  The numerical hydrodynamic modelling of beat Cepheid behavior has been a long
standing quest in which purely radiative models had failed consistently. We
find that beat pulsations occur naturally when {\it turbulent convection} is
accounted for in our hydrodynamics code. The development of a relaxation code
and of a Floquet stability analysis greatly facilitates the search for and the
analysis of beat Cepheid models. The conditions for the occurrence of beat
behavior can be understood easily and at a fundamental level with the help of
amplitude equations.

Astrophysics;Fluid Dynamics