Session: Flow Visualization and Regular Poster Session

Paper Number: 170467

170467 - 3-D Visualization of Transient Vortex Dynamics in a Three-Bladed Magnus Vertical Axis Wind Turbine 

Abstract: 

A video generated from a CFD simulation sheds light on the flow structures over a three-bladed Magnus Vertical Axis Wind Turbine (VAWT). The Magnus VAWT is designed to capture strong winds, including typhoons, and it works on wind speeds between 4 and 40 m/s. On the other hand, conventional Horizontal Axis Wind Turbines (HAWTs) can only operate at wind speeds lower than 25 m/s, despite their 40% efficiency. The complex flow physics of VAWTs, combined with the recent emergence of the Magnus VAWT concept, has resulted in limited research on its performance.

Magnus VAWT generates power by utilizing the lift force produced by the spin of its cylinders. A major challenge is to ensure consistent power generation across all cylinder positions while avoiding excessive energy input to adjust the cylinder's spin speed. To address this, a passive flow enhancement uses a flat plate positioned with a small gap relative to each cylinder. As the cylinder rotates around the rotor's axis, the plate moves synchronously around the same axis, altering flow patterns and Magnus forces to generate stable torque while keeping the cylinder's spin speed constant.

Numerical simulations were carried out using an in-house code that integrates the direct-forcing immersed boundary (DFIB) method with the finite volume method and LES turbulence model. The computations were performed on the GPGPU cluster at Taiwan’s National Center for High-performance Computing (NCHC). Using a two-way Fluid-Structure Interaction (FSI) approach at a moderate Reynolds number, the simulation captures the transient 3D vortex structures of the airflow as the turbine accelerates from a stationary state to a stable rotation. The video reveals how the flat plate modifies flow separation and transition, ensuring consistent power generation by the turbine. Thus, the study highlights the Magnus VAWT's potential as an efficient and robust renewable energy solution.

Presenting Author: Fandi Dwiputra Suprianto National Taiwan University of Science and Technology

Presenting Author Biography: