762 research outputs found
Logarithmic scaling in the near-dissipation range of turbulence
A logarithmic scaling for structure functions, in the form , where is the Kolmogorov dissipation scale and
are the scaling exponents, is suggested for the statistical
description of the near-dissipation range for which classical power-law scaling
does not apply. From experimental data at moderate Reynolds numbers, it is
shown that the logarithmic scaling, deduced from general considerations for the
near-dissipation range, covers almost the entire range of scales (about two
decades) of structure functions, for both velocity and passive scalar fields.
This new scaling requires two empirical constants, just as the classical
scaling does, and can be considered the basis for extended self-similarity
Derivative moments in turbulent shear flows
We propose a generalized perspective on the behavior of high-order derivative
moments in turbulent shear flows by taking account of the roles of small-scale
intermittency and mean shear, in addition to the Reynolds number. Two
asymptotic regimes are discussed with respect to shear effects. By these means,
some existing disagreements on the Reynolds number dependence of derivative
moments can be explained. That odd-order moments of transverse velocity
derivatives tend not vanish as expected from elementary scaling considerations
does not necessarily imply that small-scale anisotropy persists at all Reynolds
numbers.Comment: 11 pages, 7 Postscript figure
Potentialities of Muttukadu mariculture farm for green mussel culture
Experimental trials were conducted for the culture of green mussel (Perna viridis) at Muttukadu Mariculture Farm of CMFRI located near Madras using Pole culture and Bag culture methods.Studies based on the growth and production potential revealed that the location is highly suitable for green mussel mariculture
Coleroon estuary, Tamil Nadu - A potential area for edible oyster and green mussel culture
A potential area for edible oyster and green mussel cultur
On the occurrence of the black clam, Villorita cyprinoides (Gray)in Pulicat Lake
The black clam villorita cyprinodes belonging to the family corbiculidae is widely distributed in the estuaries of west coast of india
Beyond scaling and locality in turbulence
An analytic perturbation theory is suggested in order to find finite-size
corrections to the scaling power laws. In the frame of this theory it is shown
that the first order finite-size correction to the scaling power laws has
following form , where
is a finite-size scale (in particular for turbulence, it can be the Kolmogorov
dissipation scale). Using data of laboratory experiments and numerical
simulations it is shown shown that a degenerate case with can
describe turbulence statistics in the near-dissipation range , where
the ordinary (power-law) scaling does not apply. For moderate Reynolds numbers
the degenerate scaling range covers almost the entire range of scales of
velocity structure functions (the log-corrections apply to finite Reynolds
number). Interplay between local and non-local regimes has been considered as a
possible hydrodynamic mechanism providing the basis for the degenerate scaling
of structure functions and extended self-similarity. These results have been
also expanded on passive scalar mixing in turbulence. Overlapping phenomenon
between local and non-local regimes and a relation between position of maximum
of the generalized energy input rate and the actual crossover scale between
these regimes are briefly discussed.Comment: extended versio
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