Wake Flow Simulation of Vertical Axis Wind Turbines Under the Influence of the Atmospheric Boundary Layer in Complex Terrains using the Actuator Line Approach

SNIC 2018/3-484


SNIC Medium Compute

Principal Investigator:

Hans Bernhoff


Uppsala universitet

Start Date:


End Date:


Primary Classification:

20304: Energy Engineering



Fluids dynamics involved in the wake of Vertical Axis Wind Turbines (VAWT) is mainly characterized by three-dimensional effects, several models have been tested for the accurate prediction of it. For example, fully-resolved models have large computational costs since they have to solve the governing equations in local highly refined grid regions close to the blade boundary layers. This fact restricts the implementation of the model for a solution in a large scale facility (like wind farms), due to its huge computation requirements and non-viable calculation time. Another approach, is to simulate the blades by using the so-called actuator line technique, which excludes the need of solving the boundary layer flow. This fact, reduces dramatically the computational expenses and makes it feasible to run studies of the wake of VAWT and VAWT wind farms. This project is related to wind turbines aerodynamics and renewable energy production. The carried out work involves both experimental and theoretical research related to the understanding to the complex and unsteady fluid dynamics inherently involved on VAWT operating conditions under the influence of the atmospheric boundary layer (ABL) in complex terrains. An accurate and reliable simulation tool for predicting the interaction between the obtained wake of an operating VAWT and the flow in atmospheric conditions is fundamental for optimizing the design and location of wind energy facility projects. The present work studies the resulting wake from VAWT applying an actuator lines model (ALM), and also identifies the effects of the interaction between the wake structure and atmospheric boundary layer in complex terrains. In order to accomplish this goal, a fully developed ABL using the so-called recycling method. Then, operating VAWT will be placed in different locations of open sites conditions in different terrains (surface roughnesses). Obtained results are going to be compared and validated using experimental data, therefore the model will be suitable for the design of wind farms with VAWT arrays in open sites. The results will give rise to appropriate turbine and operational conditions in order to maximize the extracted power from the available wind and geography of a specific location. Furthermore, these results can be used to calculate the minimum distance between the turbines in a wind farm facility, which will reduce the construction and installation costs considerably.