Wall models for use in Large Eddy Simulations of turbulent flows with non equilibrium effects

Abstract

The main objective of this Ph.D. research project is the study, improvement and development of wall models for use in Large Eddy Simulation (LES) of turbulent flows that exhibits non-equilibrium effects. The LES approach using wall models has the objective of preventing the direct solution of turbulent dynamic structures inside the inner region of the boundary layer, which increases the computational cost for high Reynolds number flows and makes LES prohibitive. Instead, this region is modeled through wall models, reducing this computational cost so that LES can be employed in complex flows. In this sense, the use and development of wall models that are capable of correctly and efficiently capturing the physical phenomena of turbulence in this region of the boundary layer is, currently, an area of active research, especially when the flow exhibits non-equilibrium effects, such as adverse pressure gradient, boundary layer separation and laminar-turbulent transition. This research project will mainly focus on two fronts: 1) improvement/development of wall models that take into account non-equilibrium effects; 2) use of flow-sensor mechanisms to verify the laminar-turbulent transition. To accomplish such goals, the LES solver currently in use in the research group at the Computational Aerodynamics Laboratory of DCTA/IAE will be modified to add the capability of employing wall models. The results obtained using improved and/or developed wall models will be compared to experimental results and other numerical simulations from the literature so that their efficiency and accuracy can be proved, and conclusions and main contributions will be published in peer-reviewed journals. (AU)