ISSN:
1432-2250
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract We show that direct numerical simulation will yield turbulent flowfields which are strongly dependent upon computer hardware and software. A computed flow trajectory is apparently uncorrelated to the true solution of a flowfield if it is allowed to evolve over a long time, and hence is called a pseudo-orbit. This is due to the trajectory instability of chaotic turbulent flows. All is not lost, however; a long-time average of flow quantities can now be computed using a pseudo-orbit by invoking the shadowing lemma. For the inviscid flow, this time average tends to approach asymptotically the phase average as predicted by the classical ergodic theorem. Although the inviscid two-dimensional flow has no real physical importance, the existence of canonical (equilibrium) distribution permits us to examine the accuracy of time averaging based on the pseudo-orbit and its inherent limitations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00312415
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