Development and Investigation of Accurate High-Order Generalized Summation-by-Parts Discretizations for Computational Fluid Dynamics
Speaker: David Craig Penner, University of Toronto
Presentation
Seminar Slide Deck (PDF-2.6MB)
Abstract
The numerical solution of the equations governing turbulent fluid flows, whether the Reynolds-averaged Navier-Stokes equations or solely the Navier-Stokes equations, as in direct and large-eddy simulations, is computationally expensive. High-order methods have the potential to reduce this computational cost by providing higher accuracy per degree of freedom relative to low-order schemes. Spatial discretization schemes based on the generalized summation-by-parts property have been developed in recent years as a general approach for designing high-order numerical methods. This work delineates how to obtain accurate solutions and, particularly, superconvergent integral functionals when solving linear and nonlinear partial differential equations governing computational fluid dynamics problems of increasing practical relevance. The specific focus is on numerical schemes constructed on block-structured grids, where the spatial derivatives in the governing equations are approximated with high-order tensor-product generalized summation-by-parts operators.
To begin, various components of high-order flow solvers based on generalized summation-by-parts operators are developed including novel artificial dissipation operators and two approaches for high-order grid generation and refinement for traditional and element-type operators. Next, it is shown that functional superconvergence is retained for generalized summation-by-parts discretizations of the linear convection equation in curvilinear coordinates. Furthermore, four dual-consistent discretizations of the two-dimensional linear convection equation based on the mortar-element and global summation-by-parts-operator approaches are derived and characterized in terms of truncation error, solution accuracy, and functional accuracy.
Finally, using information gained from the analysis of the linear convection equation, a generalized summation-by-parts discretization for obtaining superconvergent functionals when solving sufficiently smooth problems governed by the Euler equations is proposed. Furthermore, the key features of a given discretization having an impact on solution and functional accuracy are delineated and analyzed. These features are identified to include the representation of the geometry, the approximation of the metrics, and the approximation of the wall normal in the flow tangency boundary condition.
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