  The present paper describes a combined experimental and high performance
computing study of new specific behaviors of the Strato-Rotational Instability
(SRI). The confrontation of low frequency Particle Image Velocimetry (PIV)
experimental data with Direct Numerical Simulations reveal new non-linear
phenomena and patterns not yet observed in the SRI, that can contribute for our
understanding of astrophysical flows, specially regarding phenomena related to
accretion disk theories. The experiment designed to investigate these SRI
related phenomena consists of a classical Taylor-Couette (TC) system with two
concentric cylinders that can rotate independently under stable density
stratification due to temperature gradients imposed in the axial direction. In
the present investigations, Froude numbers are between 1.5<F<4., and Reynolds
numbers vary between 300<Re<1300, while rotation ratio between outer and inner
cylinders fixed at 0.35, a value slightly smaller than the Keplerian velocity
profile, but beyond the Rayleigh limit. The same experimental configuration is
used in the Direct Numerical Simulations investigation, that uses a parallel
high-order compact scheme incompressible code that solves the Boussinesq
equations. Both simulations and experiments reveal, in agreement with recent
linear stability analyses, the occurrence of a return to stable flows with
respect to the SRI when the Reynolds numbers increase. Low frequency velocity
amplitude modulations related to two competing spiral wave modes, not yet
reported, are observed both numerically and experimentally.
