The latest development in screw compressor (helical lobed compressor) rotor profile design and rotor manufacturing machinery have prioritized basic rotor profile surface, lead and divide. However, one error that at frrst looks very basic but at the same time almost impossible to eliminate, is dealt with in this paper. The error is rotor runout.

An aeroelastic model of a smart rotor system (which incorporates blade-mounted trailing-edge flap actuators and conventional root pitch actuation) is presented in linear time invariant state space form. The servo-flap deflections are modeled as producing incremental lift and moment variations, so that any linear aerodynamic actuator can be evaluated. This smart rotor model is used to conduct pa...

The compatibility between a composite beam cross-sectional analysis based on the variational asymptotic approach, and a helicopter rotor blade model which is part of a comprehensive rotorcraft analysis code is examined. It was found that the finite element cross-sectional analysis code VABS can be combined with a moderate deflection rotor blade model in spite of the differences between the form...

This paper present a new advanced control algorithm based on continuous minimization of predicted tracking errors, to achieve torque, rotor speed and rotor flux amplitude tracking objectives. This algorithm called a new Adaptive Nonlinear Predictive Control to induction motor drive uses a combination of the adaptive observer for rotor flux and Cascaded Nonlinear Predictive Control technique. Th...

This paper proposes an adaptive flux observer for induction motors, where stator and rotor resistances are estimated in online environments. The variation of motor parameters during operation degrades the performance of the controller and the flux observer. Among the parameters of induction motors, rotor resistance is a crucial one for flux estimation, and stator resistance also becomes critica...

An aerodynamic fairing can reduce the effects of the wind turbine tower wake on the blades of a downwind rotor. Previous studies on fairing design have focused on idealized conditions and time-averaged drag reductions, whereas this is the first study to obtain and analyze unsteady velocity field data in the wake of minimum drag fairings at non-zero angles of attack, specifically designed for wi...

The renewable energy sources such as wind energy maintain to increase in popularity since they are inexhaustible and pollution-free. The horizontalaxis wind turbine has been the most common type of wind turbines but due to recent increase in popularity of personal green energy solutions, Vertical-Axis Wind Turbines (VAWT) are becoming more common. Besides two mayor rotor types of VAWTs the Darr...

This paper presents a theoretical study on omnidirectional aerial vehicles with body-frame fixed unidirectional thrusters. Omniplus multi-rotor designs are defined as the ones that allow to exert a total wrench in any direction using positiveonly lift force and drag moment (i.e., positive rotational speed) for each rotor blade. Algebraic conditions for a design to be omniplus are derived, a sim...

Owls are widely known for silent flight, achieving remarkably low noise gliding and flapping flights owing to their unique wing morphologies, which are normally characterized by leading-edge serrations, trailing-edge fringes and velvet-like surfaces. How these morphological features affect aerodynamic force production and sound suppression or noise reduction, however, is still not well known. H...

Wind Energy Conversion System (WECS) based on Doubly Fed Induction Generator (DFIG) connected to the grid is subjected to high transient currents at rotor side and rise in DC-link voltage during voltage sag at stator/grid side. To secure power system operation wind turbines have to meet grid requirements through the Low voltage ride through (LVRT) capability and contribute to grid voltage contr...