Turbulence at the CrossRoads : The Utility and13; Drawbacks of Traditional Approaches

Narasimha, R (1989) Turbulence at the CrossRoads : The Utility and13; Drawbacks of Traditional Approaches. Technical Report. National Aeronautical Laboratory, Bangalore, India.

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    Abstract

    This survey argues that traditional approaches to turbulence have led to some notable but incomplete successes, such as the establishment of a plausible connection between diffusion and correlation, and the similarity and matchability arguments of Millikan and Kolmogorov . Experience with shear flows may be summarised in the form of some basic working rules,although their validity cannot be considered beyond doubt . On the other13; hand, traditional approaches seem to ignore the wide prevalence of exponential distributions (rather than Gaussians), and have not led to any rational models for turbulent flow yet . For many decades now the scientific initiative has remained with experiment, and extensive work on coherent structures in a variety of flows has suggested novel methods of turbulence management13; and possible new candidates for quot;moleculesquot; of turbulence that may enable progress in theory . While the initiative may now be passing to computers at low Reynolds numbers, a quot;reconciliationquot; between the notions of ordered13; motion and statistical theory is considered likely in the near future, and will probably emerge from greater understanding of the apparently random occurrence of coherent events through a dynamical-systems approach .

    Item Type: Proj.Doc/Technical Report (Technical Report)
    Additional Information: This is the text of an invited lecture delivered13; at the Workshop on quot;Turbulence at the Cross13; Roads, or Whither Turbulence?quot;, organised by13; the Mathematical Sciences Institute and held13; at Cornell University during 22-24 March 1989 .
    Uncontrolled Keywords: Turbulence;Traditional approaches;Coherent structures;13; Modelling;Chaos;Exponential distributions;Working rules13; 13;
    Subjects: ENGINEERING > Fluid Mechanics and Thermodynamics
    AERONAUTICS > Aerodynamics
    Division/Department: UNSPECIFIED
    Depositing User: Deputy Head Poornima Narayana
    Date Deposited: 10 Aug 2006
    Last Modified: 24 May 2010 09:45
    URI: http://nal-ir.nal.res.in/id/eprint/1969

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