The wake of an unsteady actuator disc

Blade Element Momentum (BEM) is the most important aerodynamic analysis method for wind turbines. BEM is derived assuming stationary conditions, which limits its ability to model the unsteady aerodynamic effects. This becomes increasingly relevant for the flexible blades of current large-scale turbines, and the employment of passive and active...

Fluctuations of angle of attack and lift coefficient and the resultant fatigue loads for a large Horizontal Axis Wind turbine

Unsteady loads are a major limiting factor for further upscaling of HAWTs considering the high costs associated to strict structural requirements. Alleviation of these unsteady loads on HAWT blades, e.g. using active flow control (AFC), is of high importance. In order to devise effective AFC methods, the unsteady loading sources need to be...

Experimental Analysis of an Actuator Disk under cyclic unsteady loading

Experimental Analysis of an Actuator Disk under cyclic unsteady loading.<br/>Wind Energy is one of the cleanest forms of energy. It does not contribute to the greenhouse gases and is also one of the least expensive forms of renewable energy. Due to this, number of wind turbines are increasing annually. Therefore, it is crucial to understand the...

Investigation of the unsteady flow over a wing under gust excitation

A detailed performance investigation of the gust generator built for the Open Jet Facility wind tunnel at TU Delft is summarised in this paper. The influence of various parameters such as reduced frequency, measurement location, and excitation amplitude on the generated gust profile was quantified. In addition, unsteady lift measurements were...

Unsteady Pylon Loading for Pylon-Mounted Tractor Propellers

Verifying the Blade Element Momentum Method in unsteady, radially varied, axisymmetric loading using a vortex ring model.

Although the Blade Element Momentum method has been derived for the steady conditions, it is used for unsteady conditions by using corrections of engineering dynamic inflow models. Its applicability in these cases is not yet fully verified. In this paper, the validity of the assumptions of quasi-steady state and annuli independence of the blade...

Determination of unsteady loads on a DU96W180 airfoil with actuated flap using particle image velocimetry

The unsteady flow conditions experienced by wind turbine blades lead to fatigue loads due to gusts, that increase the cost of energy. The decrease of the impact of these unsteady loads will most certainly lead to a decrease of the cost of energy. In order to alleviate unsteady loads the Smart Rotor Blade approach [2] applies spanwise-distributed...

Rotational Augmentation Disparities in the MEXICO and UAE Phase VI Experiments

Wind turbine structures and components suffer excessive loads and premature failures when key aerodynamic phenomena are not well characterized, fail to be understood, or are inaccurately predicted. Turbine blade rotational augmentation remains incompletely characterized and understood, thus limiting robust prediction for design. Pertinent...