CAREER: Scalar Transport in High Reynolds Number Boundary Layer with Heterogeneous Roughness and Source Flux: Modeling Marine Aerosol in Coastal Regions

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The goals of this research is to better understand transport by turbulent flow over rough surfaces since this understanding is important for a broad range of scientific and engineering applications, such as pollutant transport, urban flows, pollen dispersion, air quality, propagation of electromagnetic waves for communication. This project will focus on the transport of marine aerosol in coastal regions, accounting for shore roughness and aerosol generation from waves. Transport by turbulent diffusion is common in nature, yet current understanding is based on simplistic flow cases rather than real applications. This project will drive future generations of models for turbulent diffusion processes through a physics-based approach. The integrated education plan is at the interface of STEM, boundary-layer flows, turbulence, and will have a broad impact by: 1) educating students about the role of atmospheric turbulence for environmental flows; 2) involving teams of high school and undergraduate students in research-related design projects; 3) promoting awareness about the role of boundary-layer flows for the environment through the LiDAR summer camp and exhibits for rotation in community libraries serving disadvantaged youth. This work will involve traditionally under-represented students and reflect the diverse demographics of the Dallas-Fort Worth metroplex area.This project will encompass three interrelated tasks: i) A LiDAR field campaign at the coast of Galveston Bay in Texas to perform simultaneous and co-located wind and marine aerosol measurements in the marine atmospheric boundary layer; ii) Application of machine learning models to characterize, classify and predict various turbulent processes for marine-aerosol transport; iii) Development of fully tensorial eddy-diffusivity models for scalar transport in absence of equilibrium condition in the surface layer. The goals of the proposed project are: 1) Characterize and model scalar concentration over height and streamwise direction as a function of surface roughness variability and local source flux; 2) Investigate the role of large energy-containing turbulent structures in the re-organization of aerosol concentration within the surface layer in absence of equilibrium condition; 3) Develop eddy-diffusivity models for scalar transport as a function of statistics of heterogeneous surface aerosol flux and roughness.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.