A Multi-camera Stereo DIC System for Extracting Operating Mode Shapes of Large Scale Structures

The development of the large-scale structures in three-dimensional wall jets formed using long rectangular channels with aspect ratios of 1 and 4 was investigated using measurements of the fluctuating wall pressure and point measurements of the turbulent velocity throughout the near and intermediate field. The instantaneous pressure fluctuations in both jets were laterally asymmetric causing the fluctuating wall pressure to be poorly correlated across the jet centerline. A frequency-dependent proper orthogonal decomposition (POD) of the fluctuating pressure measurements indicated that the first two mode shapes were opposite and each mode made similar contributions to the mean square fluctuations at all frequencies in order to capture the instantaneous asymmetry of the pressure field. The mode shapes in the intermediate field of both jets were strongly frequency dependent, and a subsequent wavelet analysis indicated that there are both large-scale horseshoe structures that span one-half of the jet and separate, smaller, near-wall structures located near the jet centerline. The initial development of the large-scale structures in the two jets differed, with the most energetic fluctuations being more antisymmetric in the square jet.

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Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

International Astronomical Union Colloquium ◽

10.1017/s0252921100031493 ◽

1999 ◽

Vol 173 ◽

pp. 243-248

Author(s):

D. Kubáček ◽

A. Galád ◽

A. Pravda

Keyword(s):

Image Processing ◽

Large Scale ◽

Harvard College ◽

Oak Ridge ◽

Large Scale Structures ◽

Short Period Comet ◽

Short Period ◽

Scale Structures ◽

Harvard College Observatory ◽

Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

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Large-Scale Structures in a Compressible Mixing Layer over a Cavity

AIAA Journal ◽

10.2514/1.1825 ◽

2003 ◽

Vol 41 (12) ◽

Author(s):

Jonathan Poggie ◽

Alexander J. Smits

Keyword(s):

Large Scale ◽

Mixing Layer ◽

Compressible Mixing Layer ◽

Large Scale Structures ◽

Scale Structures

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Large-scale structures predicted by linear models of wall-bounded turbulence

Journal of Physics Conference Series ◽

10.1088/1742-6596/1522/1/012006 ◽

2020 ◽

Vol 1522 ◽

pp. 012006

Author(s):

S. Symon ◽

S. J. Illingworth ◽

I. Marusic

Keyword(s):

Large Scale ◽

Linear Models ◽

Large Scale Structures ◽

Scale Structures ◽

Wall Bounded Turbulence

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The organization and control of an evolving interdependent population

Journal of The Royal Society Interface ◽

10.1098/rsif.2015.0044 ◽

2015 ◽

Vol 12 (108) ◽

pp. 20150044 ◽

Cited By ~ 5

Author(s):

Dervis C. Vural ◽

Alexander Isakov ◽

L. Mahadevan

Keyword(s):

Evolutionary Game Theory ◽

Large Scale ◽

Social Evolution ◽

Evolutionary Game ◽

Large Scale Structures ◽

External Perturbations ◽

Emergence Of Cooperation ◽

Scale Structures ◽

And Control ◽

Evolutionarily Stable

Starting with Darwin, biologists have asked how populations evolve from a low fitness state that is evolutionarily stable to a high fitness state that is not. Specifically of interest is the emergence of cooperation and multicellularity where the fitness of individuals often appears in conflict with that of the population. Theories of social evolution and evolutionary game theory have produced a number of fruitful results employing two-state two-body frameworks. In this study, we depart from this tradition and instead consider a multi-player, multi-state evolutionary game, in which the fitness of an agent is determined by its relationship to an arbitrary number of other agents. We show that populations organize themselves in one of four distinct phases of interdependence depending on one parameter, selection strength. Some of these phases involve the formation of specialized large-scale structures. We then describe how the evolution of independence can be manipulated through various external perturbations.

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