Earth Science and Engineering, Imperial College London
Doi
Abstract
Interpolation of discrete FIelds arises frequently in computational physics.
This thesis focuses on the novel implementation and analysis of Galerkin
projection, an interpolation technique with three principal advantages over
its competitors: it is optimally accurate in the L2 norm, it is conservative,
and it is well-defined in the case of spaces of discontinuous functions.
While these desirable properties have been known for some time, the implementation
of Galerkin projection is challenging; this thesis reports the first
successful general implementation.
A thorough review of the history, development and current frontiers of
adaptive remeshing is given. Adaptive remeshing is the primary motivation
for the development of Galerkin projection, as its use necessitates the interpolation
of discrete fields. The Galerkin projection is discussed and the
geometric concept necessary for its implementation, the supermesh, is introduced.
The efficient local construction of the supermesh of two meshes
by the intersection of the elements of the input meshes is then described.
Next, the element-element association problem of identifying which elements
from the input meshes intersect is analysed. With efficient algorithms for
its construction in hand, applications of supermeshing other than Galerkin
projections are discussed, focusing on the computation of diagnostics of simulations
which employ adaptive remeshing. Examples demonstrating the effectiveness
and efficiency of the presented algorithms are given throughout.
The thesis closes with some conclusions and possibilities for future work
