Ava Shahrokhi
University of Sheffield,UK
Title: The effect of the upstream wind conditions on the performance of a vertical axis wind turbine
Biography
Biography: Ava Shahrokhi
Abstract
The effect of the upstream velocity profile on the performance of a rotating vertical axis wind turbine has been investigated using the SST k-ω turbulence model in unsteady flow conditions. This study is a part of the European Project New innovative solutions, components and tools for the integration of wind energy in urban and peri-urban areas (acronym SWIP, project no. 608554). Recently more vertical axis wind turbines (VAWTs) have been installed in urban areas than before. This is due to the fact that VAWTs are more appropriate for urban regions than Horizontal Axis Wind Turbines (HAWTs). They are known to perform better in urban regions compared to horizontal axis wind turbines as they do not require alignment to the oncoming air flow. However, the wind flow speed in urban regions is substantially influenced by the structure of the buildings in the location that the turbine is to be installed. This includes changes in the angle of attack and formation of a vortex flow in the upstream wind that will alter the performance of the wind turbine. This work involves numerical simulation of the air flow around VAWT blades that is installed on the roof of a building. A turbulent velocity profile has been considered at the inlet which is exposed to the building obstacle before it encounters the VAWT. The computational fluid dynamics techniques will be based on Reynolds averaging of the unsteady Navier-Stokes equations (URANS). Since flow separation, and in particular dynamic stall, are key flow processes occurring in such applications, e.g. see the authors group previous investigations (Almohammadi, et al., 2012) and (Almohammadi, et al., 2015), the transient SST k-ω is the most appropriate turbulence model for wind turbine flow simulations with dynamic stalls. Therefore, this turbulence modelling scheme is utilized for the simulations of the VAWT. The results of the disturbed air flow around the turbine are compared with the case of an undisturbed wind at the inlet.