  Aspects of transition mechanisms on a $14^{\circ}$ sharp-nosed ogive-cylinder
at Mach~$6$ are elucidated by considering linear and nonlinear disturbance
evolution of freestream stochastic and wave packet forcing at different
locations downstream of the ogive-cylinder junction. The spectral response of
the stochastic forcing displays favorable agreement with experimental
observations from AFRL on which the configuration is based. Intermittent wave
packets are generated from small-amplitude continuous freestream pressure
forcing. Linear wave packet evolution reveals that Mack modes are the dominant
primary instabilities, followed by relatively weaker first-mode waves. The
non-linear wavepacket displays a three-legged wall pressure perturbation
signature, which is traced to spanwise curvature effects, and fundamental
resonance is the dominant secondary instability mechanism. At higher amplitudes
of excitation, weak signatures of sub-harmonic and oblique resonance phenomena
are identified. Downstream placement of the small-amplitude disturbance
diminishes receptivity of first-mode waves; however, with high-amplitude
forcing, the location of actuation does not significantly vary the disturbance
evolution signature or the secondary instability mechanisms.
