A team of scientists led by Hui Hu from the Iowa State University are conducting tests on mini turbine models to establish how the placement of wind turbines amidst hills and valleys affects the productivity of a wind farm.
As of now, there is very little information available on the effects of uneven ground over the performance of wind turbines. The mini turbines were created at the Aerodynamic/Atmospheric Boundary Layer Wind and Gust Tunnel built at a cost of $1.25 million.
For the purpose of the study, the mini turbine has been fitted with small generators inside the nacelles to measure production of power. Sensors have been fitted at the base of the mini turbine to measure wind load on the turbine and the turbine tower. Advanced techniques such as particle image velocimetry has been used to measure wind vortices, wind flow fields and the wind energy generated by the blades of the turbine. Results of the study have established that turbines located in hilly areas are met with higher wind loads as compared to wind turbines located on flat terrains.
Wind flowing on hilly areas also has the ability to recover its power faster than the wind flowing on flat terrain. Data collected from the tunnel suggests that wind turbines located on flat terrain at a distance equal to six times their diameter lost 13% of wind power production as opposed to 3% power production loss from turbines located in the same distance on hilly terrain. This means that wind turbines can be placed closer to each other in hilly areas. The next phase of the project will involve constructing an array of nine turbines in the big wind tunnel of Iowa State.