Unformatted text preview: FUNDAMENTAL AND CONCEPTUAL
ASPECTS OF TURBULENT FLOWS
Arkady Tsinober Professor and Marie Curie Chair in Fundamental and Conceptual Aspects of Turbulent Flows
Institute for Mathematical Sciences and Department of Aeronautics, Imperial College London
Lectures series as a part of the activity within the frame
of the Marie Curie Chair “Fundamental and Conceptual
Aspects of Turbulent Flows”.
We absolutely must leave room for doubt or there is no progress and no learning.
There is no learning without posing a question. And a question requires
doubt...Now the freedom of doubt, which is absolutely essential for the
development of science, was born from a struggle with constituted authorities...
FEYNMANN LECTURES XVII-XVIII AN OVERVIEW OF
ILL POSED CONCEPTIONS
Dealing with conceptual aspects one
encounters the issue of misconceptions
.. even wrong theories may help in
designing machines, FEYNMAN, 1996
FEYNMAN, Dealing with conceptual aspects of turbulence research leads necessarily
to address the misconceptions which emerged during more than a century
of turbulence research attempting to achieve some physical understanding
(picture) of this enigmatic phenomenon. Hence the purpose of this
overview is twofold. Apart of critical aspect the main constructive aim and
outcome from addressing a variety of misconceptions is a possibility of
deeper understanding the problems to be encountered and coped with.
Gradient transport ideas (which have been around since
the beginning) are understood to be wrong in principle,
yet they are used daily with moderate success by
industry. Understanding how this can be (it is
thoroughly explained by Tennekes and Lumley, 1972, p.
57) sheds light on turbulence. KRAICHNAN 1976 EXAMPLES ON
A REMINDING LEONARDO-REYNOLDS, DECOMPOSITION - conceptually correct*.
Note that there is a conceptual difference between RANS and LES.
BOUSSINESQ, EDDY VISCOSITY/diffusivity and mixing length BOUSSINESQ EDDY conceptually incorrect, though useful as an empirical tool**....
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