Career: Unraveling the Spatial Structure of Turbulence in the Atmospheric Boundary Layer using Unmanned Aerial Vehicles

Humanity is immersed within the atmospheric boundary layer, making it perhaps the most important turbulent ow on the planet. Thus, deciphering the chaotic, nonlinear dynamics of its turbulence has great fundamental and practical importance. For example, heat, mass and momentum transport between the Earth's surface and the atmosphere is controlled to a large extent by the action of coherent turbulent motions that form and evolve within the atmospheric boundary layer. Understanding these structures and their interactions is therefore essential for understanding the transport processes. However, gaining such insight is hindered by the enormous range of spatial and temporal scales which exist in atmospheric turbulence, and the current lack of experimental tools to properly study all relevant scales. This CAREER research plan addresses this challenge by introducing the novel approach of using highly instrumented and autonomous unmanned aerial vehicles to spatially interrogate the turbulent ow structure over a wide range of length scales. These vehicles represent a new paradigm in our ability to study the extraordinarily interesting and diverse turbulent physics within the atmospheric boundary layer. In this research plan, their capabilities will be used to gain new insight into the turbulence structure near the surface and use detailed investigations of the coherent structures populating the atmospheric boundary layer to inform structure-based models of wall-bounded turbulence. Use of unmanned aerial vehicles is also an integral component of the CAREER education plan, which seeks to exploit student excitement and interest in these vehicles to engage undergraduates by bringing them out of the classroom and into the laboratory to experience research-based learning. The education plan also seeks to leverage this excitement through outreach activities such as involving high school students in team based design competitions and hands-on learning laboratories that aim to stimulate their intellectual growth and become a platform for their education in fundamental science. The Intellectual Merit of the proposed work rests on resolving a wide range of spatial scales within one of the most challenging ows in turbulence research. These measurements, using a unique combination of experimental tools and analysis techniques, will ll a void in traditional atmospheric boundary layer research capabilities and create new understanding of its structure, organization and transport processes. For example, the measurements conducted while pioneering this new experimental approach will (a) answer questions about the hierarchy of coherent structures which form in the atmospheric boundary layer; (b) characterize the eects of atmospheric stability and terrain on the behavior of these structures; (c) advance understanding as to how the dynamics of these structures contribute to transport processes within the atmospheric boundary layer; and (d) produce eddy-structure based models capable of accounting for the complex boundary conditions which exist in atmospheric ows. The Broader Impact of the work is given by its contribution to fundamental research in high Reynolds number boundary layer turbulence. Predicting the transport of heat, momentum, water vapor and pollutants due to this turbulence is a crucial part of many scientic disciplines such as hydrology, agriculture, air quality management and wind engineering. Therefore improved understanding will have a positive broader impact by oering societal improvements in many ways, including modeling of weather and climate patterns, improving prediction of loading experienced by buildings, improving energy recovery through wind farm planning and operation, or by improving our ability to track pollutants trapped in the atmospheric boundary layer. The educational component of this eort will impact the recruitment and retention of students into STEM undergraduate and graduate programs within Kentucky by capturing the interest and imagination of students at all levels and encouraging their involvement in fundamental science through a fun and exciting technical challenge. By participating in a fundamental scientic study where they can experience the discovery and thrill of breaking new ground, the students will be energized and motivated towards a scientic career.