 Modeling Turbulence in the Numerical Simulation of Stratified Atmospheric Boundary Layers THESIS TOPIC PROPOSAL Institute: Budapest University of Technology and Economics mechanical engineering Géza Pattantyús-Ábrahám Doctoral School of Mechanical Engineering Thesis supervisor: Gergely Kristóf Location of studies (in Hungarian): BME Department of Fluid Mechanics Abbreviation of location of studies: ÁT Description of the research topic: a.) Preliminaries: In engineering practice, there is an increasing demand for the numerical simulation of atmospheric boundary layers, as their results can contribute to a better exploitation of wind energy, improvement of air quality, and this is the fastest and most cost-effective way of structural wind load analysis in cases where standards cannot be applied. Several studies deal with the numerical simulation of the atmospheric boundary layer, but only a few of them consider the effects of thermal stratification. Accordingly, the comprehensive examination of arbitrarily stratified atmospheric boundary layers remains a great challenge, since the models required for the simulation of micro-scale phenomena are only available to a limited extent. b.) Aim of research: The aim of the research is to adapt the turbulence models of general purpose CFD software to stratified atmospheric flows, to develop the necessary physical parameterization schemes and the small-scale simulation methodology, i.e. to create the background for a comprehensive numerical analysis. c.) Tasks, main items, necessary time: • Literature research: literature and case studies related to neutral and stratified, turbulent atmospheric boundary layers. Testing of a dynamic core suitable for handling the stratified atmosphere. (1st year) • Adaptation of turbulence models, development and implementation of boundary conditions and parameterization schemes based on scale-resolving simulations. (1st-3rd years) • Data collection: Collection of data from field measurements and small sample (wind tunnel) experiments. Verification and validation of the developed tools using the collected data. (2nd-3rd years) • Preparation of the Dissertation. (4th year) d.) Required equipment: HPC access and a workstation are required for development and testing. These are available. Since the dynamic core has been implemented in an open source software environment, currently available academic licenses may be required for comparison purposes only. e.) Expected scientific results: Adapted turbulence models, new boundary conditions and physical parameterization schemes, as well as a new simulation methodology, which enable a comprehensive investigation of atmospheric boundary layers with arbitrary stratification and the efficient use of such calculations in industrial tasks. f.) References: Salma, I., Farkas, Á., Weidinger, T., & Balogh, M. (2023). Firework smoke: Impacts on urban air quality and deposition in the human respiratory system. ENVIRONMENTAL POLLUTION, 328. http://doi.org/10.1016/j.envpol.2023.121612 Balogh, M., & Parente, A. (2015). Realistic boundary conditions for the simulation of atmospheric boundary layer flows using an improved k–ε model. JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS, 144, 183–190. http://doi.org/10.1016/j.jweia.2015.01.010 Balogh, M., Parente, A., & Benocci, C. (2012). RANS simulation of ABL flow over complex terrains applying an Enhanced k-ε model and wall function formulation: Implementation and comparison for fluent and OpenFOAM. JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS, 104–106, 360–368. http://doi.org/10.1016/j.jweia.2012.02.023 Balogh, M., & Kristóf, G. (2010). Fine scale simulation of turbulent flows in urban canopy layers. IDŐJÁRÁS / QUARTERLY JOURNAL OF THE HUNGARIAN METEOROLOGICAL SERVICE, 114(1–2), 135–148. Kristóf, G., Rácz, N., & Balogh, M. (2009). Adaptation of Pressure Based CFD Solvers for Mesoscale Atmospheric Problems. BOUNDARY-LAYER METEOROLOGY, 131(1), 85–103. http://doi.org/10.1007/s10546-008-9325-7 Required language skills: English Number of students who can be accepted: 1 Deadline for application: 2024-10-15 |