In forward flight, slowing down a rotor alleviates compressibility effects on the advancing side blade tip, extending cruise speed limit, and inducing high-advance-ratio flight regime. Previous wind tunnel tests have shown that an articulated trimmed to zero hub moment generates limited thrust at high advance ratios, because needs be against retreating with significant reverse flow, where is in...

most of the methods that have been proposed for speed estimation of induction machines require the rotor and the stator resistance to change in the normal operating range. on the other hand, estimation of the rotor resistance requires rotor speed. in this paper, after studying conditions for simultaneous estimation of rotor speed and rotor resistance, a method for simultaneous estimation of rot...

This paper presents an analysis of a model problem, consisting of two interacting rigid rings, for the rotation of molecules in liquid He. Due to Bose symmetry, the excitation of the rotor corresponding to a ring of N helium atoms is restricted to states with integer multiples of N quanta of angular momentum. This minimal model shares many of the same features of the rotational spectra that hav...

The nonlinear coupling vibration and bifurcation of a high-speed centrifugal compressor with a labyrinth seal and two air-film journal bearings are presented in this paper. The rotary shaft and disk are modeled as a rigid Jeffcott rotor. Muszynska’s model is used to express the seal force with multiple parameters. For air-film journal bearings, the model proposed by Zhang et al. is adopted to e...

Abstract Purpose In this paper, the analytic solution for a free rotatory motion under influence of motor limited power is investigated; we aim to prove that carrier body close rotation about fixed axis depending upon problem's parameters and initial conditions. Method Tensor calculus tools, asymptotic method, kinematic equations (EOM) are used. Results At large time, properties solutions syste...

A procedure that automatically identifies internal rotation modes and rotating groups during the normal mode vibrational analysis is outlined, and an improved approximation to the corrections for the thermodynamic functions is proposed. The identification and the characterization of the internal rotation modes require no user intervention and make extensive use of the information imbedded in th...