  We propose a simple computational procedure in order to resolve the
degeneracy, which invariably exists on the background of fluid motion
associated with a channel of infinite extent. The procedure is applied to
elucidate the bifurcation structure for the particular case of laterally heated
flow with the addition of a perturbative Poiseuille flow component. The
introduction of a symmetry breaking perturbation as the simplest imperfection
alters the bifurcation tree of the original shear flow. As a result, the
previously unknown higher order nonlinear solutions for the unperturbed flow
are discovered, without implementing classical stability theory.
