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Analysis of High-Order Element Types for Implicit Large Eddy Simulation

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Analysis of High-Order Element Types for Implicit Large Eddy Simulation

Pereira, Carlos A (2019) Analysis of High-Order Element Types for Implicit Large Eddy Simulation. Masters thesis, Concordia University.

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Abstract

The use of high-order schemes continues to increase, with current methods becoming more robust and reliable. The resolution of complex turbulent flows using Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) can be computed more efficiently with high-order methods such as the Flux Reconstruction (FR) approach. We make use of the implicit form of LES, referred to
as ILES, in which the numerical dissipation of the spatial scheme passively filters high-frequency modes and no subgrid scale turbulent model is explicitly implemented. Therefore, given the inherent three-dimensional behaviour of turbulent flows, it is important to understand the spectral characteristics of spatial discretizations in three dimensions. The dispersive and dissipative properties
of hexahedra, prismatic and tetrahedral element types are compared using Fourier Analysis. This comparison is performed on a per degree of freedom basis to assess their suitability for ILES in terms of computational cost. We observe dispersion relations that display non-smooth behaviour for tetrahedral and prismatic elements, with the presence of jumps in the solution modes. Semilogarithmic
plots of the numerical error are presented. We observe that the amount of numerical dissipation and dispersion added by hexahedral elements is the least, followed by prisms and finally tetrahedra. We validate our analysis comparing results obtained on computational domains with comparable computational cost against DNS data. Hexahedral elements have the best agreement with the reference data, followed by prismatic and finally tetrahedral elements, which is consistent with the spectral analysis.

Divisions:Concordia University > Gina Cody School of Engineering and Computer Science > Mechanical, Industrial and Aerospace Engineering
Item Type:Thesis (Masters)
Authors:Pereira, Carlos A
Institution:Concordia University
Degree Name:M.A. Sc.
Program:Mechanical Engineering
Date:July 2019
Thesis Supervisor(s):Vermeire, Brian
Keywords:Von Neumann Analysis, Flux Reconstruction, High-order methods
ID Code:985613
Deposited By: Carlos Pereira
Deposited On:06 Feb 2020 02:36
Last Modified:06 Feb 2020 02:36
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