Aerodynamic noise from a wind turbine is numerically modeled in the time domain. An analytic trailing edge noise model is used to determine the unsteady pressure on the blade surface. The far-field noise due to the unsteady pressure is calculated using the acoustic analogy theory. By using a strip theory approach, the two-dimensional noise model is applied to rotating wind turbine blades. The n...

The design of an advanced controller for wind turbine load mitigation is presented. The controller is based on Nonlinear Dynamic Inversion control methods combined with Pseudo Control Hedging to account for the actuator limits and a two degree of freedom control system for the collective pitch control of the rotor blades. The controller uses wind speed measurement information to adjust to wind ...

A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of modern turbines almost exclusive use of horizontal axis rotors. The aerodynamic design principles fo...

The present work deals with the structural analysis of turbine blades and modeling of turbine blades. A common failure mode for turbine machines is high cycle of fatigue of compressor and turbine blades due to high dynamic stresses caused by blade vibration and resonance within the operation range of the machinery. In this work, proper damping system will be analyzed to reduce the vibrating bla...

A new mechanism responsible for structural life consumption due to resonant fatigue in turbine blades, or vanes, is presented and explained. A rotating blade or vane in a gas turbine can change its contour due to erosion and/or material build up, in any of these instances, the surface pressure distribution occurring on the suction and pressure sides of blades-vanes can suffer substantial modifi...

Vertical axis wind turbine blades undergo dynamic stall due to the large 1 angle of attack variation they experience during a turbine rotation. Particle image 2 velocimetry on a pitching and surging airfoil was used to perform time resolved 3 measurements at blade Reynolds numbers near turbine operating conditions of 105. 4 These experiments were compared to simulations performed in the rotatin...

This paper describes a model based control approach for individually adjusting the pitch of wind turbine blades and thereby attenuating the effect of asymmetric wind loads. It is assumed that measurements of local inflow along each blade are available. This effectively provides an estimate of the load distribution along the blades. The load estimates are used in a predictive setup where inflow ...

Out of the total wind turbine failure events, blade damage accounts for a substantial part, with some studies estimating it at around 23%. Current operation and maintenance (O&M) practices typically make use of corrective type maintenance as the basic approach, implying high costs for repair and replacement activities as well as large revenue losses, mainly in the case of offshore wind farms. T...

The high replacement costs of aircraft gas turbine blades and vanes have created a fast-growing, highly-specialized segment of the aircraft repair industry. The economic rationale for repair in lieu of replacement is prima facie. The metallurgical rationale is less certain, but satisfactory flight performance over the past twenty-five years at least attests to the technical adequacy of blade an...

The LOX-Hydrogen J-2X Rocket Engine, which is proposed for use as an upper-stage engine for numerous earth-to-orbit and heavy lift launch vehicle architectures, is presently in the design phase and will move shortly to the initial development test phase. Analysis of the design has revealed numerous potential resonance issues with hardware in the turbomachinery turbine-side flow-path. The analys...