EAGER: Visualizing Land-to-Atmosphere Exchanges due to Wind Turbines Under Stratified Flows

Portland State University, Portland OR

Investigators

Abstract

0953053 Cal For wind turbine arrays, a land-to-atmosphere exchange is enhanced by introducing atmospheric thermal stable or unstable stratification. The stable atmospheric turbulence boundary layer (ATBL) reduces flow turbulence. Wind turbine arrays have been claimed to dry the land during stable conditions (typically during evening), thus having a possible impact on agriculture, also possibly affecting wind erosion. Understanding complex interactions of a stratified ATBL and a wind turbine array is the goal of this study. To acquire the proper understanding, the relationship between the energy and heat fluxes occurring within the wind farm and their interactions with the periodic wake generated by the wind turbine is vital. In this study, wind tunnel experiments at Portland State University are planned to visualize the mixing processes of a stratified turbulent boundary layer with and without a wind turbine. The experimental objectives are to control stratification carefully and parametrically and then perform flow visualization in the generated flows. Vertical motions/exchanges of turbulence between a single wind turbine and ATBL will guide conclusions about the land-to-atmosphere exchanges, thus motivating further questions. This study can have significant impact on understanding needed for large-scale deployment of such technology. These preliminary visualizations will motivate further studies of these flows for a larger suite of experiments, taking into account wind turbine array rather than a single turbine. This preliminary information will help prepare more detailed plans for future submissions to NSF-Fluid Dynamics program and/or the NSF-Energy for Sustainability program to study such interactions in detail.