Bending, buckling and vibration behaviors of nonlocal Timoshenko beams are investigated in this research using a variational approach. At first, the governing equations of the nonlocal Timoshenko beams are obtained, and then the weak form of these equations is outlined in this paper. The Ritz technique is selected to investigate the behavior of nonlocal beams with arbitrary boundary conditions ...

this paper presents the aerodynamic design and economical evaluation of a 200 kw site specific wind turbine for the province of semnan in iran. by designing site specific wind turbines, the cost of energy which is calculated out of the annual energy production and also the cost of manufacturing the rotor are minimized. the aerodynamic design is based on the well-known blade element momentum the...

Rotor cage faults as broken rotor bars, increased bars resistance and end-ring faults can be caused by thermal stresses, due to overload, overheating and thus mechanical stresses, magnetic stresses and dynamic stresses due to shaft torques. Environmental stresses as contamination or abrasion also contributes to the rotor cage faults. The rotor cage faults can also lead to the shaft vibration an...

A rotor-router walk is a deterministic version of a random walk, in which the walker is routed to each of the neighbouring vertices in some fixed cyclic order. We consider here directed covers of graphs (called also periodic trees) and we study several quantities related to rotor-router walks on directed covers. The quantities under consideration are: order of the rotor-router group, order of t...

The problem of controlling a sensorless induction motor (i.e. without rotor speed measurements) is addressed. Smooth reference signals for rotor speed and rotor ‡ux modulus are required to be tracked exponentially and globally. Only semiglobal solutions have been recently obtained in the literature. A global solution is presented for current-fed induction motors which makes use of a novel rotor...

As a wind turbine extracts energy from the wind, induced wind velocities, lower than the freestream velocity, will be present both upstream and downstream of the rotor. In this study, the upstream induction zone of a 225 kW horizontal axis Vestas V27 wind turbine located at the Danish Technical University’s Risø campus is investigated using a scanning Light Detection and Ranging (lidar) system....

Title of Dissertation: Computational Investigation of Micro-Scale Coaxial Rotor Aerodynamics in Hover Vinod K. Lakshminarayan, Doctor of Philosophy, 2009 Dissertation directed by: Dr. James D. Baeder Department of Aerospace Engineering In this work, a compressible Reynolds-Averaged Navier Stokes (RANS) solver is extended to investigate the aerodynamics of a micro-scale coaxial rotor configurati...

Turbocharger is a high speed rotor system supported by a pair of floating ring bearings which comprise of double oil films. The stability of its rotor system is governed by not only the structure of the rotor but also by the nonlinear hydrodynamic force of two oil films. In this paper, a lumped dynamics model is developed for a turbocharger rotor system. In order to investigate the nonlinear be...

This paper presents an active vibration control scheme to reduce unbalanceinduced synchronous vibration in rotor-bearing systems supported on two ball bearings, one of which can be automatically moved to control the effective rotor length and, as an immediate consequence, the rotor stiffness. This dynamic stiffness control scheme, based on frequency analysis, speed control and acceleration sche...

The rotor eddy current losses of a high-speed permanent magnet synchronous motor reduce the efficiency of the motor and increase the temperature rise of the rotor. In severe cases, the permanent magnet of the rotor can be demagnetized, affecting the safe operation of the motor. In this paper, an analytical model of rotor eddy current losses calculation based on Maxwell equations is introduced. ...