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Oono, Yoshitsugu San Martin, Luis Emilio 2012-05-17T17:10:54Z 2012-05-17T17:10:54Z 10000-01-01 1998 Many nonequilibrium phenomena are spatially extended, and the most popular means to model them is the partial differential equation (PDE). Resultant PDEs are, however, often nonlinear, defying analytical approaches. Thus, devising efficient numerical algorithms to solve PDEs is important for the study of nonequilibrium systems, and has traditionally been considered a major branch of applied mathematics. A computationally efficient model that captures the crucial physics of a system can be an efficient numerical solver of the PDE describing the system. This general idea will be illustrated in terms of solvers for hyperbolic equations, such as those describing advection in fluids and linear wave propagation. We demonstrate in this thesis that a conscious pursuit of physics essence can lead to useful numerical algorithms. From this point of view, the development of solvers for physically meaningful PDEs can be considered a branch of applied physics. Our strategy for deriving new algorithms is to implement the crucial physics, as faithfully as possible, in order to reproduce the phenomenon inside the computer. The solution of the PDE is obtained, in this approach, as a by-product of the correct implementation of the physics of the problem. After explaining the derivation of algorithms for the solution of advection in fluids, we present a new methodology to derive algorithms for wave propagation problems, based on the modeling of Huygens' principle. The new methodology can be used to derive higher-order algorithms systematically. We explain why these algorithms are advantageous in comparison to standard higher-order finite-difference algorithms, and present tests and evaluations of the new schemes. We give new algorithms for the wave equation and Maxwell's equations, including the implementation of some types of boundary conditions. We conclude by suggesting extensions of the method to related problems. Submitted by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-17T17:10:54Z No. of bitstreams: 1 1998_sanmartin.pdf: 4009852 bytes, checksum: b58508ff044f307b1d0c5a6a0cc8928f (MD5) Made available in DSpace on 2012-05-17T17:10:54Z (GMT). No. of bitstreams: 1 1998_sanmartin.pdf: 4009852 bytes, checksum: b58508ff044f307b1d0c5a6a0cc8928f (MD5) Previous issue date: 1998 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Elizabeth Kent (eckent2@illinois.edu) on 2012-05-17T17:10:54Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:10:38-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: thesis thesis U of I Only 4128763 http://hdl.handle.net/2142/30854 en ©1998 Luis Emilio San Martin partial differential equations PDE hyperbolic equations Physics motivated algorithms for partial differential equations Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.