V. Pagneux et A. Maurel, A NUMERICAL STUDY OF INSTABILITIES IN CON FINED OPEN FLOWS, Comptes rendus de l'Academie des sciences. Serie II. Mecanique, physique, chimie, astronomie, 319(6), 1994, pp. 617-623
We present a general method of analysing instability dynamics. Numeric
al simulations are performed with a code using a spectral finite eleme
nt method for incompressible, unsteady flows. The presented systems ar
e found to undergo a transition to an unstable state at a critical Rey
nolds number. The method consists in extracting the perturbation field
at various steps of the temporal development. The field in the linear
regime gives the spatial eigenfunction and we observe its modificatio
n due to non-linear behaviours. This distorsion is extracted to determ
ine the parts of the flow field crucial for the non-linear dynamics.