Zhuyin Ren

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This work addresses the construction and use of low-dimensional invariant manifolds to simplify complex chemical kinetics. Typically, chemical kinetic systems have a wide range of time scales. As a consequence, reaction trajectories rapidly approach a hierarchy of attracting manifolds of decreasing dimension in the full composition space. In previous(More)
Pulmonary embolism is the third leading cause of death in hospitalized patients in the US. Vena cava filters are medical devices inserted into the inferior vena cava (IVC) and are designed to trap thrombi before they reach the lungs. Once trapped in a filter, however, thrombi disturb otherwise natural flow patterns, which may be clinically significant. The(More)
Computational calculations of combustion problems involving real fuels with chemistry represented by detailed mechanisms are prohibitive, due to the large number of species and reactions involved. We present a new combined dimension reduction and tabulation algorithm for the efficient implementation of combustion chemistry. In this algorithm, the dimension(More)
Nomenclature Roman Symbols A mapping gradient matrix with components A ij ≡ ∂f i /∂x j A maximum number of table entries per processor allowed A * critical number of ISAT table entries a number of table entries in a serial calculation a i total number of tabulated table entries in all processors in group i in the adaptive strategy a * L maximum number of(More)
Detailed chemical kinetics is an integral component for predictive simulation of turbulent flames and is important for reliable prediction of flames and emissions. Major challenges of incorporation of detailed chemistry in flame simulations are induced by the large number of chemical species and the wide range of timescales involved in detailed kinetics. In(More)
— Progress is reported in the integration of two methodologies to enable the efficiency application of realistic combustion chemistry in computational fluid dynamics. These methodologies are ICE-PIC (invariant constrained-equilibrium edge manifold using the pre-image curve method) for dimension reduction, and ISAT (in situ adaptive tabulation) for(More)
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