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Department of Mechanical Engineering
Stanford University
Abstract-
This talk will provide an overvierw of two very different flow modeling
projects of very different scale. The first is Stanford's ASCI program
on the simulation of the complete time-dependent three-dimensional
turbulent flow and combustion in a modern aircraft engine. New ideas in
both large eddy simulation of combustion and Reynolds-averaged
turbulence modeling for turbomachinery will be discussed. This program
is using the world's most powerful supercomputers provided by the
Department of Energy, and is a very large team effort. The second
project is a simple zero-dimensional model for internal combustion
engines, developed by the speaker for instructional and engineering use
and designed to run rapidly on personal computers. The program
incorporates a simple turbulence model that enables it to mimic effects
of turbulence enhancement on engine performance. A new approximate model
for unsteady manifold gasdynamics, based on the methods of
characteristics and using a system of ordinary differential-difference
equations for properties at the nodes somewhat akin to lumped parameter
analysis, will be described. However, unlike lumped parameter analysis,
in which the capacitance is in the nodes and the resistance is in the
branches, in this model (and in a manifold) the capacitance is in the
branches and the main resistance is at the nodes. Other continuous
dynamical systems in which nodal methods like this might be used will be
mentioned.
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