Dynamic Analysis of Vertical Axis Wind Turbines Under Unsteady Wind Conditions Considering Inertial Effects

Abstract Wind energy plays a pivotal role in the global transition to renewable energy, contributing significantly to the reduction of carbon emissions. Vertical Axis Wind Turbines (VAWTs) are simple to design, capture wind from any direction, and perform well in turbulent conditions, but leveraging these advantages requires a clear understanding of their dynamics in real-world conditions. This study analyzes the dynamic response of VAWTs under unsteady wind conditions, where varying wind speeds cause changes in angular velocity, addressing limitations of conventional analyses assuming constant angular velocity. Rotor response is examined for three wind profiles—an increasing step, a decreasing step, and gusts with noise—by tracking rotor torque and angular velocity over time using the dynamic equation of motion and accounting for rotor inertia. A parametric analysis evaluates the effect of inertia by analyzing VAWTs’ response to step increases and decreases in wind speed for five different inertia values. Results show that rotor inertia moderates speed fluctuations, delays angular velocity response to abrupt wind changes, and filters noise-induced fluctuations under gusts. Rotor torque peaks and stabilizes with step increases, drops sharply before stabilizing with step decreases, and fluctuates sharply under gusts. Higher inertia is associated with longer times for angular velocity and rotor torque to reach steady-state, highlighting the critical role of inertia in dynamic behavior of VAWTs.