Nonlinear Forced Oscillation of a Rotating Disk Excited at a Point Fixed in Space. (Combination Tones near Primary Resonance Points)

Nonlinear forced oscillation of a rotating circular disk excited at a point fixed in space is considered.For theoretical analysis, modal equations are derived from the govering partial differential equations.Then, based on these modal equations, the characteristics of oscillation induced by a harmonic excitation are investigated.Numerical calculation is conducted for a typical case in which the excitation frequency is near the primary resonance points of the forward and backward traveling wave modes.It is shown that near the primary resonance point of the backward traveling mode, the forward traveling mode oscillation occurs in addition to the backward traveling mode oscillation, and conversely, near the primary resonance point of the forward traveling mode, the backward traveling mode oscillation occurs in addition to the forward traveling mode oscillation.An experimental analysis is also conducted, which confirms the validity of the theoretical analysis.