Applicability of Dynamic Inflow Models of HAWT in Yawed Flow Conditions

Horizontal axis wind turbines (HAWTs) experience yaw misalignments due to the physical limitations of yaw controllers and various novel active yaw controls. Moreover, the motion of floating offshore wind turbines (FOWTs) accelerates yaw misalignment. The blade element momentum (BEM) method is widely used due to its computational efficiency for...

A new dynamic inflow model for vertical-axis wind turbines

This paper presents a new dynamic inflow model for vertical-axis wind turbines (VAWTs). The model uses the principle of Duhamel's integral. The indicial function of the inflow- and crossflow-induction required to apply Duhamel's integral is represented by an exponential function depending on the thrust coefficient and the azimuthal position....

New dynamic-inflow engineering models based on linear and nonlinear actuator disc vortex models

Two new engineering models are presented for the aerodynamic induction of a wind turbine under dynamic thrust. The models are developed using the differential form of Duhamel integrals of indicial responses of actuator disc type vortex models. The time constants of the indicial functions are obtained by the indicial responses of a linear and...

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...

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...