Application of Time-dependent Fourier Analysis to Nonlinear Pulsational Stellar Models

The variation of the modal content of the numerical hydrodynamical integration with various initializations of nonlinear RR Lyrae models is studied with the aid of a time-dependent Fourier analysis. The authors discuss the sensitivity of the derived temporal behavior of the amplitudes and phases to the parameters of the method. New light is shed on many very interesting details of mode interaction during the transient phases, not seen before, and a better assessment of the final state of the amplitude evolution results.