EAPSI: A Next-Generation of Wind Fence with Multi-Scale Fractal Structure

Mcclure Sarah, Bay Village OH

Investigators

Abstract

Understanding and controlling atmospheric instabilities, such as abrupt air movements resulting from a storm, is of great interest to those who study fluid flow as alterations of atmospheric turbulence can be used to reduce strong winds. It is important, therefore, to understand how engineered structures such as porous wind fences or windbreaks affect various incoming flows. This research will explore multi-scale fractal structure-induced turbulence to better control air currents. The research will be conducted in collaboration with Professor Sang Joon Lee of Pohang University of Science and Technology (POSTECH), an expert in quantitative flow visualization, experimental fluid mechanics, bluff body aerodynamics and bio-fluid flows. Because this study is concerned with atmospheric turbulence for new-generation wind fences, it is imperative to have the appropriate laboratory equipment to simulate real-life conditions. The host laboratory has multiple wind tunnels, including an atmospheric boundary-layer wind tunnel, and various flow measurement systems, providing an excellent location to conduct this research. Insights from this research will contribute to engineering more effective wind fences to limit snow/sand deposition on critical infrastructure such as roads and bridges and to reduce the overall side impact of wind on structures themselves. Previous studies found that a regular mono-scale grid fence of 50% porosity and a bottom gap of 10% of the fence height are considered to be optimal over a flat surface. Since significant differences in turbulent structure have been noted using fractal wind fences with this porosity criteria, the goal of this research is to advance knowledge on the induced flow structure and the turbulence kinetic energy transport of 1D and 2D multi-scale fractal fences in atmospheric boundary-layer conditions. Specifically, whole velocity fields will be systematically measured around the fractal fences by Particle Image Velocimetry (PIV) techniques to uncover effects of key parameters of fractal fences on turbulence for a wide range of Reynolds numbers. Ultimately, this research will assist design of new-generation fractal wind fences which can extract sufficient kinetic energy from the mean wind flow to promote snow/sand deposition and prevent particle remobilization from excessive turbulent stresses. This award is funded in collaboration with the National Research Foundation of Korea.