Exercise Problems

1. Who was the person first analysed rotor dynamics problem, however, wrongly predicted that it is impossible to operate rotors at very high speeds?
2. Define the natural frequency and the critical speed of a rotor system?
3. How to distinguish the rigid and flexible rotors?
4. How many critical speeds would be for a two-disc massless-flexible shaft rotor system?
5. Who first experimentally reported that it was possible to rotate the rotor safely at very high speed?
6. Who clarified theoretically the confusion that it is possible to rotate the rotor safely at very high speed?
7. Who were the first to use the terms the whirling motion and the critical speed?
8. Whether the natural frequency could be dependent on the spin speed of the rotor? If yes then when?
9. What is the most common fault causes a synchronous in a rotor system?
10. In a synchronous whirl of a rotor what would be the whirl frequency?
11. For a perfectly balanced rotor rotating at a speed, what would be the frequency of whirl when it is perturbed from its equilibrium?
12. In a general motion of a rotor what would be the whirl frequency?
13. Whether bearings and foundations have any effect on the critical speed of a rotor?
14. What is the internal and external damping in a rotor system?
15. Is there any difference between the rigid and flexible rotor dynamic balancing?
16. What is a Campbell diagram?
17. Explain the inertia asymmetry and a shaft asymmetry in a rotor system? What are the effects of these asymmetries in rotor behaviour?
18. What are the different active control mechanisms, which can be applied in rotor systems?