This paper presents a means for reducing the torque variation during the revolution of a vertical-axis water turbine (VAWaterT) by increasing the blade number. For this purpose, twodimensional CFD analyses have been performed on a straight-bladed Darrieus-type rotor. After describing the computational model and the relative validation procedure, a complete campaign of simulations, based on full...

This paper presents a detailed study of the extended Kalman filter (EKF) for estimating the rotor resistance and rotor speed of an induction motor drive. The overall structure of the EKF is reviewed and the various system vectors and matrices are defined. By including the rotor resistance and rotor speed as a state variables, the EKF equations are established from a discrete two-axis model of t...

Unsteady helicopter rotor aerodynamics are complicated. This paper reviews some of the fundamentals and newer developments of unsteady helicopter aerodynamics. Rotor flow is beautiful and complex. Visualizing rotor flow allows for an appreciation of the following theories and solution attempts as well as nature’s complexities. The flow through a helicopter rotor with forward motion is shown in ...

Abstract: This paper presents an exact input-output linearization control scheme for rotor speed and rotor flux control of induction motor drive. In this scheme the motor model, is described in the fixed stator frame, and it is linearized, using exact inputoutput linearization technique, allowing a decoupled control of rotor flux and torque. To avoid the use of mechanical sensor, the rotor spee...

0. Introduction J.A. Green 6, x4] introduces codeterminants, which are products of pairs of natural basis elements of the Schur algebra S(n; r). These are shown to be parametrised by pairs of row-semistandard tableaux of shape , where 2 (n; r). If both the tableaux are standard, and the composition is dominant, then the codeterminant is said to be standard. The set of standard codeterminants fo...

In this paper, the classic straightening out theorem from di erential geometry is used to derive necessary and su cient conditions for locally converting rectangular di erential inclusions to constant rectangular di erential inclusions. Both scalar and coupled di erential inclusions are considered. The results presented in this paper have use in the area of computer aided veri cation of hybrid ...

This paper considers the negative gradient trajectories associated with the modified total squared curvature functional ∫ k2 + ν ds. The focus is on the limiting behavior as ν tends to zero from the positive side. It is shown that when ν = 0 spaces of curves exist in which some trajectories converge and others diverge. In one instance the collection of critical points splits into two subsets. A...

w x Hodge and Pedoe 5 constructed bases of the homogeneous coordinate rings of the Schubert varieties in the Grassmannian, consisting of certain products of Plucker coordinates called standard monomials. Lakshmibai, ̈ w x Musili, and Seshadri 6 have generalized this theory extensively, giving standard monomial bases of the spaces of global sections of certain line bundles over unions of Schubert...

Repetitive learning control was examined for active vibration control of rotor. A novel modification of a gradient-based repetitive learning control algorithm was developed. The stability of the algorithm was studied and the algorithm was tested on a rotor test rig. The experiments showed that repetitive learning control attenuated efficiently rotor vibrations excited by rotor unbalances. In ad...

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...