Studies in nonlinear problems of energy
Emphasis has been on combustion and flame propagation. The research program was on modeling, analysis and computation of combustion phenomena, with emphasis on transition from laminar to turbulent combustion. Nonlinear dynamics and pattern formation were investigated in the transition. Stability of combustion waves, and transitions to complex waves are described. Combustion waves possess large activation energies, so that chemical reactions are significant only in thin layers, or reaction zones. In limit of infinite activation energy, the zones shrink to moving surfaces, (fronts) which must be found during the analysis, so that (moving free boundary problems). The studies are carried out for limiting case with fronts, while the numerical studies are carried out for finite, though large, activation energy. Accurate resolution of the solution in the reaction zones is essential, otherwise false predictions of dynamics are possible. Since the the reaction zones move, adaptive pseudo-spectral methods were developed. The approach is based on a synergism of analytical and computational methods. The numerical computations build on and extend the analytical information. Furthermore, analytical solutions serve as benchmarks for testing the accuracy of the computation. Finally, ideas from analysis (singular perturbation theory) have induced new approaches to computations. The computational results suggest new analysis to be considered. Among the recent interesting results, was spatio-temporal chaos in combustion. One goal is extension of the adaptive pseudo-spectral methods to adaptive domain decomposition methods. Efforts have begun to develop such methods for problems with multiple reaction zones, corresponding to problems with more complex, and more realistic chemistry. Other topics included stochastics, oscillators, Rysteretic Josephson junctions, DC SQUID, Markov jumps, laser with saturable absorber, chemical physics, Brownian movement, combustion synthesis, etc.
- Research Organization:
- Northwestern Univ., Evanston, IL (United States)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-87ER25027
- OSTI ID:
- 7038802
- Report Number(s):
- DOE/ER/25027-6; ON: DE92018551
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
ANALYTICAL SOLUTION
CHEMICAL PHYSICS
CHEMICAL REACTIONS
COMBUSTION
DIFFUSION
DISTURBANCES
DOCUMENT TYPES
ELECTRONIC EQUIPMENT
EQUIPMENT
FLAME PROPAGATION
FLUID FLOW
HYSTERESIS
JOSEPHSON JUNCTIONS
JUNCTIONS
LAMINAR FLOW
LASERS
MARKOV PROCESS
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
OSCILLATIONS
OSCILLATORS
OXIDATION
PERTURBATION THEORY
PHYSICS
PROGRESS REPORT
PULSES
RESEARCH PROGRAMS
STABILITY
STOCHASTIC PROCESSES
SUPERCONDUCTING JUNCTIONS
THERMOCHEMICAL PROCESSES
TURBULENCE