THESIS
2018
xv, 75 pages : color illustrations ; 30 cm
Abstract
In this thesis, a high order reconstruction in the finite volume (FV) approach
is achieved by a more fundamental form of the fifth order WENO reconstruction
in the framework of orthogonally‒curvilinear coordinates, for solving hyperbolic
conservation equations. The derivation employs a piecewise parabolic
polynomial approximation to the zone averaged values (Q̄
i) to reconstruct the
right (q
i+), middle (q
iM), and left (q
i‒) interface values. The grid dependent
linear weights of the WENO are recovered by inverting a Vandermonde‒like
linear system of equations with spatially varying coefficients. A scheme for
calculating the linear weights, optimal weights, and smoothness indicator on
a regularly‒/irregularly‒spaced grid in orthogonally‒curvilinear coordinates is
proposed. A grid...[
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In this thesis, a high order reconstruction in the finite volume (FV) approach
is achieved by a more fundamental form of the fifth order WENO reconstruction
in the framework of orthogonally‒curvilinear coordinates, for solving hyperbolic
conservation equations. The derivation employs a piecewise parabolic
polynomial approximation to the zone averaged values (Q̄
i) to reconstruct the
right (q
i+), middle (q
iM), and left (q
i‒) interface values. The grid dependent
linear weights of the WENO are recovered by inverting a Vandermonde‒like
linear system of equations with spatially varying coefficients. A scheme for
calculating the linear weights, optimal weights, and smoothness indicator on
a regularly‒/irregularly‒spaced grid in orthogonally‒curvilinear coordinates is
proposed. A grid independent relation for evaluating the smoothness indicator is
derived from the basic definition. Finally, a computationally efficient extension
to multi-dimensions is proposed along with the procedures for flux and source
term integrations. Analytical values of the linear weights, optimal weights, and
weights for flux and source term integrations are provided for a regularly‒spaced
grid in Cartesian, cylindrical, and spherical coordinates. Conventional fifth order
WENO‒JS can be fully recovered in the case of limiting curvature (R → ∞).
The fifth order finite volume WENO‒C (orthogonally‒curvilinear version of
WENO) reconstruction scheme is tested for several 1D and 2D benchmark tests
involving smooth and discontinuous
flows in cylindrical and spherical coordinates.
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