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This project was focused on the use and placement of vertical axis wind turbines (VAWTs). Studies were focused on areas not typically addressed in previous work; small wind at very low elevations (i.e. within the boundary layer). Numerical studies were made of how VAWTs function as well as the potential wind environments they may be placed in. A simplified numerical code, based on two-dimensional potential flow functions, was developed to model flow around buildings and other structures. The code allows a rapid determination of regions where flow may experience speed-up and where turbulence may result.

Experimental facilities were designed and constructed that allowed scale model VAWTs to be tested in both a water channel and a low speed wind tunnel. Anemometer towers were also designed and constructed for measuring wind conditions at regional test sites. A large amount of experimental data was gathered from these facilities. The data covers performance measures of specific VAWT models, measured flow fields around VAWT models, measured wind flow fields at multiple test locations, and numerically predicted flow fields around structures (e.g. buildings and grain bins).

The project observed that the wake region behind a VAWT can extend as far as four diameters and will be offset toward the side of rotation. This will affect how VAWTs can be packed together into arrays. For Savonius designs, an increase in performance can be obtained by placing a second VAWT appropriate in this wake region. However, the same result was not seen for helical designs. Overall, final recommendations on placement could not be made. Recent industry research indicates that some VAWTs perform better when placed in areas of higher turbulence. This project was unable to verify those results. A better understanding of how VAWTs perform at different levels of turbulent intensity will be needed before final placement recommendations can be made.

A large number or outreach and dissemination activities were conducted to a range of audiences, including K-12, industry, the general public, as well as state and national political figures. Awareness of renewable energy and wind power in particular, was raised. Thirty-six students (undergraduate and graduate) participated actively in this project. The conducted research as well as interacted with public audiences in dissemination activities.

Several recommendations have been made for continuing or future work. With the experimental infrastructure developed through this project, some of these topics are already being pursued. Other topics related to energy research could also be undertaken in the future.


Mechanical and Civil Engineering