  Transition from steady state to intermittent chaos in the cubical lid-driven
flow is investigated numerically. Fully three-dimensional stability analyses
have revealed that the flow experiences an Andronov-Poincar\'e-Hopf bifurcation
at a critical Reynolds number $Re_c$ = 1914. As for the 2D-periodic lid-driven
cavity flows, the unstable mode originates from a centrifugal instability of
the primary vortex core. A Reynolds-Orr analysis reveals that the unstable
perturbation relies on a combination of the lift-up and anti lift-up mechanisms
to extract its energy from the base flow. Once linearly unstable, direct
numerical simulations show that the flow is driven toward a primary limit cycle
before eventually exhibiting intermittent chaotic dynamics. Though only one
eigenpair of the linearized Navier-Stokes operator is unstable, the dynamics
during the intermittencies are surprisingly well characterized by one of the
stable eigenpairs.
