Vertical axis wind turbines (VAWTs) are proposed as an alternative to the more commonly used horizontal axis wind turbines (HAWTs) due to the potential increase in packing density (reduction in distance between turbines) that is possible with VAWTs. But for VAWTs to be more widely adopted and for their advantages to be maximized, more work is needed in the turbine and farm designs. This project aims at improving the design of VAWTS and their configurations in large farms.This work has major impacts on the adaptation and development of wind as an alternative energy source in the US and worldwide; wind is already the fastest growing energy source in the US (as a percent increase on previous installed capacity for a given source). The project team has generated an artificially thickened boundary layer in the MAE wind tunnel in order to test scale models of wind turbines. Tests of the original flow indicated that improvements were required to remove the cross-stream variations in the profile. They have now achieved a flow that closely matches the wind profile, turbulence levels, and spectrum seen in the atmospheric boundary layer. Their tests on a model VAWT in the original thick boundary layer are now being repeated and performance results are expected shortly. They have also implemented a VAWT representation (that resolves the force on each individual blade) in a large eddy simulation code and we proceeding with validation of the approach and modeling of various configurations of multiple turbines to understand their interactions and optimize farm configuration.
Author: Elie Bou-Zeid and Alexander Smits
Publication: Princeton Environmental Institute
Year Published: 2013