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124
Nonoscillatory Central Schemes For Multidimensional Hyperbolic Conservation Laws
 SIAM J. Sci. Comput
, 1998
"... We construct, analyze, and implement a new nonoscillatory highresolution scheme for twodimensional hyperbolic conservation laws. The scheme is a predictorcorrector method which consists of two steps: starting with given cell averages, we first predict pointvalues which are based on nonoscillatory ..."
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Cited by 80 (14 self)
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We construct, analyze, and implement a new nonoscillatory highresolution scheme for twodimensional hyperbolic conservation laws. The scheme is a predictorcorrector method which consists of two steps: starting with given cell averages, we first predict pointvalues which are based on nonoscillatory piecewiselinear reconstructions from the given cell averages; at the second corrector step, we use staggered averaging, together with the predicted midvalues, to realize the evolution of these averages. This results in a secondorder, nonoscillatory central scheme, a natural extension of the onedimensional secondorder central scheme of Nessyahu and Tadmor [J. Comput. Phys., 87 (1990), pp. 408448]. As in the onedimensional case, the main feature of our twodimensional scheme is simplicity. In particular, this central scheme does not require the intricate and timeconsuming (approximate) Riemann solvers which are essential for the highresolution upwind schemes; in fact, even the com...
A ‘‘vertically Lagrangian’’ finitevolume dynamical core for global models
 Weather Rev
, 2004
"... A finitevolume dynamical core with a terrainfollowing Lagrangian controlvolume discretization is described. The vertically Lagrangian discretization reduces the dimensionality of the physical problem from three to two with the resulting dynamical system closely resembling that of the shallow wate ..."
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Cited by 74 (9 self)
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A finitevolume dynamical core with a terrainfollowing Lagrangian controlvolume discretization is described. The vertically Lagrangian discretization reduces the dimensionality of the physical problem from three to two with the resulting dynamical system closely resembling that of the shallow water system. The 2D horizontaltoLagrangiansurface transport and dynamical processes are then discretized using the genuinely conservative fluxform semiLagrangian algorithm. Time marching is splitexplicit, with large time steps for scalar transport, and small fractional steps for the Lagrangian dynamics, which permits the accurate propagation of fast waves. A mass, momentum, and total energy conserving algorithm is developed for remapping the state variables periodically from the floating Lagrangian controlvolume to an Eulerian terrainfollowing coordinate for dealing with ‘‘physical parameterizations’ ’ and to prevent severe distortion of the Lagrangian surfaces. Deterministic baroclinic wavegrowth tests and longterm integrations using the Held–Suarez forcing are presented. Impact of the monotonicity constraint is discussed. 1.
Reconstructing Volume Tracking
 J. Comput. Phys
, 1997
"... A new algorithm for the volume tracking of interfaces in two dimensions is presented. The algorithm is based upon a welldefined, secondorder geometric solution of a volume evolution equation. The method utilitizes local discrete material volume and velocity data to track interfaces of arbitrari ..."
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Cited by 71 (2 self)
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A new algorithm for the volume tracking of interfaces in two dimensions is presented. The algorithm is based upon a welldefined, secondorder geometric solution of a volume evolution equation. The method utilitizes local discrete material volume and velocity data to track interfaces of arbitrarily complex topology. A linearitypreserving, piecewise linear interface geometry approximation ensures that solutions generated retain secondorder spatial accuracy. Secondorder temporal accuracy is achieved by virtue of a multidimensional unsplit time integration scheme. We detail our geometricallybased solution method, in which material volume fluxes are computed systematically with a set of simple geometric tasks. We then interrogate the method by testing its ability to track interfaces through large (yet controlled) topology changes, whereby an initially simple interface configuration is subjected to vortical flows. Numerical results for these strenuous test problems provide evi...
Numerical Methods For Hyperbolic Conservation Laws With Stiff Relaxation I. Spurious Solutions
 SIAM J. Sci. Comput
, 1992
"... . We consider the numerical solution of hyperbolic systems of conservation laws with relaxation using a shock capturing finite difference scheme on a fixed, uniform spatial grid. We conjecture that certain a priori criteria insure that the numerical method does not produce spurious solutions as the ..."
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Cited by 55 (2 self)
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. We consider the numerical solution of hyperbolic systems of conservation laws with relaxation using a shock capturing finite difference scheme on a fixed, uniform spatial grid. We conjecture that certain a priori criteria insure that the numerical method does not produce spurious solutions as the relaxation time vanishes. One criterion is that the limits of vanishing relaxation time and vanishing viscosity commute for the viscous regularization of the hyperbolic system. A second criterion is that a certain "subcharacteristic" condition be satisfied by the hyperbolic system. We support our conjecture with analytical and numerical results for a specific example, the solution of generalized Riemann problems of a model system of equations with a fractional step scheme in which Godunov's method is coupled with the backward Euler method. We also apply our ideas to the numerical solution of stiff detonation problems. 1. Introduction. Hyperbolic systems of conservation laws with relaxation ...
An Adaptive Cartesian Grid Method For Unsteady Compressible Flow In Irregular Regions
 J. Comput. Phys
, 1993
"... In this paper we describe an adaptive Cartesian grid method for modeling timedependent inviscid compressible flow in irregular regions. In this approach a body is treated as an interface embedded in a regular Cartesian mesh. The single grid algorithm uses an unsplit secondorder Godunov algorithm fo ..."
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Cited by 48 (14 self)
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In this paper we describe an adaptive Cartesian grid method for modeling timedependent inviscid compressible flow in irregular regions. In this approach a body is treated as an interface embedded in a regular Cartesian mesh. The single grid algorithm uses an unsplit secondorder Godunov algorithm followed by a corrector applied to cells at the boundary. The discretization near the fluidbody interface is based on a volumeoffluid approach with a redistribution procedure to maintain conservation while avoiding time step restrictions arising from small cells where the boundary intersects the mesh. The single grid Cartesian mesh integration scheme is coupled to a conservative adaptive mesh refinement algorithm that selectively refines regions of the computational grid to achieve a desired level of accuracy. Examples showing the results of the combined Cartesian grid integration/adaptive mesh refinement algorithm for both two and threedimensional flows are presented. (This page intent...
Third Order Nonoscillatory Central Scheme For Hyperbolic Conservation Laws
"... . A thirdorder accurate Godunovtype scheme for the approximate solution of hyperbolic systems of conservation laws is presented. Its two main ingredients include: #1. A nonoscillatory piecewisequadratic reconstruction of pointvalues from their given cell averages; and #2. A central differencing ..."
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Cited by 47 (15 self)
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. A thirdorder accurate Godunovtype scheme for the approximate solution of hyperbolic systems of conservation laws is presented. Its two main ingredients include: #1. A nonoscillatory piecewisequadratic reconstruction of pointvalues from their given cell averages; and #2. A central differencing based on staggered evolution of the reconstructed cell averages. This results in a thirdorder central scheme, an extension along the lines of the secondorder central scheme of Nessyahu and Tadmor [NT]. The scalar scheme is nonoscillatory (and hence  convergent), in the sense that it does not increase the number of initial extrema (as does the exact entropy solution operator). Extension to systems is carried out by componentwise application of the scalar framework. In particular, we have the advantage that, unlike upwind schemes, no (approximate) Riemann solvers, fieldbyfield characteristic decompositions, etc., are required. Numerical experiments confirm the highresolution content of...
Approximate Solutions of Nonlinear Conservation Laws and Related Equations
, 1997
"... During the recent decades there was an enormous amount of activity related to the construction and analysis of modern algorithms for the approximate solution of nonlinear hyperbolic conservation laws and related problems. To present some aspects of this successful activity, we discuss the analytical ..."
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Cited by 34 (11 self)
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During the recent decades there was an enormous amount of activity related to the construction and analysis of modern algorithms for the approximate solution of nonlinear hyperbolic conservation laws and related problems. To present some aspects of this successful activity, we discuss the analytical tools which are used in the development of convergence theories for these algorithms. These include classical compactness arguments (based on BV a priori estimates), the use of compensated compactness arguments (based on H^1compact entropy production), measure valued solutions (measured by their negative entropy production), and finally, we highlight the most recent addition to this bag of analytical tools  the use of averaging lemmas which yield new compactness and regularity results for nonlinear conservation laws and related equations. We demonstrate how these analytical tools are used in the convergence analysis of approximate solutions for hyperbolic conservation laws and related equations. Our discussion includes examples of Total Variation Diminishing (TVD) finitedifference schemes; error estimates derived from the onesided stability of Godunovtype methods for convex conservation laws (and their multidimensional analogue  viscosity solutions of demiconcave HamiltonJacobi equations); we outline, in the onedimensional case, the convergence proof of finiteelement streamlinediffusion and spectral viscosity schemes based on the divcurl lemma; we also address the questions of convergence and error estimates for multidimensional finitevolume schemes on nonrectangular grids; and finally, we indicate the convergence of approximate solutions with underlying kinetic formulation, e.g., finitevolume and relaxation schemes, once their regularizing effect is quantified in terms of the averaging lemma.
Solution of Two Dimensional Riemann Problem of Gas Dynamics by Positive Schemes
 SIAM J. Sci. Comput
, 1995
"... The positivity principle and positive schemes to solve multidimensional hyperbolic systems of conservation laws have been introduced in [8]. Some numerical experiments presented there show how well the method works. In this paper we use positive schemes to solve Riemann problems for twodimensional ..."
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Cited by 33 (1 self)
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The positivity principle and positive schemes to solve multidimensional hyperbolic systems of conservation laws have been introduced in [8]. Some numerical experiments presented there show how well the method works. In this paper we use positive schemes to solve Riemann problems for twodimensional gas dynamics.
SemiImplicit Spectral Deferred Correction Methods For Ordinary Differential Equations
 Comm. Math. Sci
, 2003
"... A semiimplicit formulation of the method of spectral deferred corrections (SISDC) for ordinary di#erential equations with both sti# and nonsti# terms is presented. Several modifications and variations to the original spectral deferred corrections method by Dutt, Greengard, and Rokhlin concerning t ..."
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Cited by 30 (13 self)
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A semiimplicit formulation of the method of spectral deferred corrections (SISDC) for ordinary di#erential equations with both sti# and nonsti# terms is presented. Several modifications and variations to the original spectral deferred corrections method by Dutt, Greengard, and Rokhlin concerning the choice of integration points and the form of the correction iteration are presented. The stability and accuracy of the resulting ODE methods for both sti# and nonsti # problems are explored analytically and numerically. The SISDC methods are intended to be combined with the method of lines approach to yield a flexible framework for creating higherorder semiimplicit methods for partial di#erential equations. A discussion and numerical examples of the SISDC method applied to advectiondi#usion type equations are included. The results suggest that higherorder SISDC methods are a competitive alternative to existing RungeKutta and linear multistep methods based on the accuracy per function evaluation.
An Experimental Evaluation of the Parallel I/O Systems of the IBM SP and Intel Paragon Using a Production Application
, 1996
"... We present the results of an experimental evaluation of the parallel I/O systems of the IBM SP and Intel Paragon using a real threedimensional parallel application code. This application, developed by scientists at the University of Chicago, simulates the gravitational collapse of selfgravita ..."
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Cited by 25 (13 self)
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We present the results of an experimental evaluation of the parallel I/O systems of the IBM SP and Intel Paragon using a real threedimensional parallel application code. This application, developed by scientists at the University of Chicago, simulates the gravitational collapse of selfgravitating gaseous clouds. It performs parallel I/O by using library routines that we developed and optimized separately for the SP and Paragon. The I/O routines perform twophase I/O and use the parallel file systems PIOFS on the SP and PFS on the Paragon. We studied the I/O performance for two different sizes of the application. In the small case, we found that I/O was much faster on the SP. In the large case, open, close, and read operations were only slightly faster, and seeks were significantly faster, on the SP; whereas, writes were slightly faster on the Paragon. The communication required within our I/O routines was faster on the Paragon in both cases. The highest read bandwidth ...