This paper studies various Hopf bifurcations in the two-dimensional plane
Poiseuille problem. For several values of the wavenumber α, we obtain
the branch of periodic flows which are born at the Hopf bifurcation of the
laminar flow. It is known that, taking α≈1, the branch of periodic
solutions has several Hopf bifurcations to quasi-periodic orbits. For the first
bifurcation, previous calculations seem to indicate that the bifurcating
quasi-periodic flows are stable and go backwards with respect to the Reynolds
number, Re. By improving the precision of previous works we find that the
bifurcating flows are unstable and go forward with respect to Re. We have
also analysed the second Hopf bifurcation of periodic orbits for several
α, to find again quasi-periodic solutions with increasing Re. In this
case the bifurcated solutions are stable to superharmonic disturbances for Re
up to another new Hopf bifurcation to a family of stable 3-tori. The proposed
numerical scheme is based on a full numerical integration of the Navier-Stokes
equations, together with a division by 3 of their total dimension, and the use
of a pseudo-Newton method on suitable Poincar\'e sections. The most intensive
part of the computations has been performed in parallel. We believe that this
methodology can also be applied to similar problems.Comment: 23 pages, 16 figure