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Tarik Dzanic
(Advisor: Prof. Oefelein]
will defend a master’s thesis entitled,
ODE-based Non-Equilibrium Wall Shear Stress Modeling for Large Eddy Simulation
On
Wednesday, July 24 at 1:30 p.m.
Montgomery Knight Building 317
Abstract
For high Reynolds number flows, wall modeling is essential for performing large eddy simulation at a reasonable computational cost. In this work, a novel low-cost ODE-based non-equilibrium wall model is introduced for wall shear stress modeling in LES. Using polynomial approximations of the pressure gradient and convective terms obtained from interpolation of the LES solution, as opposed to direct evaluation of these gradients within the wall model, the governing wall model equations reduce from coupled PDEs to uncoupled ODEs, solvable at a significantly cheaper computational cost. Additionally, as a result of the decoupling of the wall model equations, a further decrease in computational cost is obtained by solving the steady form of the wall model equations and modeling the effects of the temporal evolution on the wall shear stress. The effects of polynomial degree on the accuracy of the wall shear stress predictions were explored, and an empirical lag model was built to model the unsteady effects without requiring the solution of a time-stepping problem. Wall resolved simulations of separated flow around the NASA wall mounted hump and an iced airfoil were performed and used as a reference for the comparison of the non-equilibrium wall model to a commonly used equilibrium wall model. Notable improvements in the prediction of the mean flow and skin friction coefficient were seen with negligible computational cost increase.
Committee
