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Please use this identifier to cite or link to this item: https://dspace.lboro.ac.uk/2134/16617

Title: Unstructured mesh methods for stratified turbulent flows
Authors: Zhang, Zhao
Keywords: Unstructured prismatic tetrahedral mesh
Stratified
Turbulent
Shear
Incompressible flows
Anelastic PDE
NFT MPDATA
LES
ILES
DES
Edge-based median dual
Atmospheric
Engineering
Issue Date: 2015
Publisher: © Zhao Zhang
Abstract: Developments are reported of unstructured-mesh methods for simulating stratified, turbulent and shear flows. The numerical model employs nonoscillatory forward in-time integrators for anelastic and incompressible flow PDEs, built on Multidimensional Positive Definite Advection Transport Algorithm (MPDATA) and a preconditioned conjugate residual elliptic solver. Finite-volume spatial discretisation adopts an edge-based data structure. Tetrahedral-based and hybrid-based median-dual options for unstructured meshes are developed, enabling flexible spatial resolution. Viscous laminar and detached eddy simulation (DES) flow solvers are developed based on the edge-based NFT MPDATA scheme. The built-in implicit large eddy simulation (ILES) capability of the NFT scheme is also employed and extended to fully unstructured tetrahedral and hybrid meshes. Challenging atmospheric and engineering problems are solved numerically to validate the model and to demonstrate its applications. The numerical problems include simulations of stratified, turbulent and shear flows past obstacles involving complex gravity-wave phenomena in the lee, critical-level laminar-turbulence transitioning and various vortex structures in the wake. Qualitative flow patterns and quantitative data analysis are both presented in the current study.
Description: A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.
URI: https://dspace.lboro.ac.uk/2134/16617
Appears in Collections:PhD Theses (Mechanical, Electrical and Manufacturing Engineering)

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