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## Polymer statistics in a random flow with mean shear

Journal of Fluid Mechanics. 2005. P. 251-260.

We consider the dynamics of a polymer with finite extensibility placed in a chaotic flow
with large mean shear, to explain how the polymer statistics changes with Weissenberg
number, Wi, the product of the polymer relaxation time and the Lyapunov exponent
of the flow, ¯ λ. The probability distribution function (PDF) of the polymer orientation
is peaked around a shear-preferred direction, having algebraic tails. The PDF of the
tumbling time (separating two subsequent flips), τ , has a maximum estimated as ¯λ−1.
This PDF shows an exponential tail for large τ and a small-τ tail determined by the
simultaneous statistics of the velocity PDF. Four regimes of Wi are identified for
the extension statistics: one below the coil–stretched transition and three above the
coil–stretched transition. Emphasis is given to explaining these regimes in terms of
the polymer dynamics.

Kolokolov I., JETP Letters 2010 Vol. 92 No. 2 P. 107-109

The joint distribution function of two distances between three Lagrangian particles has been calculated in the
problem of chaotic twodimensional transport ...

Added: February 2, 2017

Kolokolov I., Lebedev V., Chertkov M. et al., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 1995 Vol. 51 No. 6 P. 5609-5627

Steady statistics of a passive scalar advected by a random two-dimensional flow of an incompressible fluid is described in the range of scales between the correlation length of the flow and the diffusion scale. This corresponds to the so-called Batchelor regime where the velocity is replaced by its large-scale gradient. The probability distribution of the ...

Added: March 28, 2017

Kolokolov I., Physics Letters A 2017 Vol. 381 P. 1036-1040

The correlation tensors of magnetic field in a two-dimensional chaotic flow of conducting fluid are studied. It is shown that there is a stage of resistive evolution where the field correlators grow exponentially with time. The two-and four-point field correlation tensors are computed explicitly in this stage in the framework of Batchelor–Kraichnan–Kazantsev model. They demonstrate ...

Added: February 14, 2017

Kolokolov I., Chertkov M., Vergassola M., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 1997 Vol. 56 No. 5 P. 5483-5499

Random advection of a Lagrangian tracer scalar field u (t,x) by a one-dimensional, spatially smooth and
short-correlated in time velocity field is considered. Scalar fluctuations are maintained by a source concentrated
at the integral scale L. The statistical properties of both scalar differences and the dissipation field are analytically
determined, exploiting the dynamical formulation of the model. The ...

Added: March 6, 2017

Kolokolov I., Gamba A., Journal of Statistical Physics 1996 Vol. 85 No. 3 P. 489-499

We present a functional integration method for the averaging of continuous productsPt ofN×N random matrices. As an application, we compute exactly the statistics of the Lyapunov spectrum ofPt. This problem is relevant to the study of the statistical properties of various disordered physical systems, and specifically to the computation of the multipoint correlators of a passive scalar ...

Added: March 8, 2017

Kolokolov I., Chertkov M., Gamba A., Physics Letters A 1994 Vol. 192 No. 5-6 P. 435-443

We describe a new functional integral method for the computation of averages containing chronological exponentials of random matrices of arbitrary dimension. We apply these results to the rigorous study of the statistics of a passive scalar advected by a large-scale N-dimensional flow. In the delta-correlated case the statistics of the rate of line stretching appears to ...

Added: March 28, 2017

Kolokolov I., Nguyen Thanh T., Physics Letters A 2012 Vol. 376 P. 1836-1838

We study mixing of passive scalar by a chaotic velocity field with a relatively strong regular shear
component. We show that the tail of partition distribution function (PDF) of coarse-grained passive scalar
field differs qualitatively from the corresponding asymptotics in the case of isotropic flow statistics. ...

Added: December 28, 2016

Kolokolov I., Journal of Physics A: Mathematical and Theoretical 2017 Vol. 50 No. 155501 P. 1-12

The two-point correlation tensor of small-scale fluctuations of magnetic field B in a two-dimensional chaotic flow is studied. The analytic approach is developed in the framework of the Kraichnan–Kazantsev model. It is shown that the growth of the field fluctuations takes place in an essentially resistive regime and stops at large times in accordance with ...

Added: March 28, 2017

Kolokolov I., Falkovich G., Chertkov M. et al., Physical Review Letters 1999 Vol. 83 No. 20 P. 4065-4068

Kinematic dynamo theory is presented here for turbulent conductive fluids. We describe how inhomogeneous magnetic fluctuations are generated below the viscous scale of turbulence where the spatial smoothness of the velocity permits a systematic analysis of the Lagrangian path dynamics. We find analytically the moments and multipoint correlation functions of the magnetic field at small ...

Added: March 5, 2017

Kolokolov I., Chertkov M., Vergassola M., Physical Review Letters 1998 Vol. 80 P. 512

A model of scalar turbulent advection in compressible flow is analytically investigated. It is shown that, depending on the dimensionality d of space and the degree of compressibility of the smooth advecting velocity field, the cascade of the scalar is direct or inverse. If d>4 the cascade is always direct. For a small enough degree of compressibility, the cascade ...

Added: March 5, 2017

Kolokolov I., Lebedev V., Kogan V., Journal of Physics A: Mathematical and Theoretical 2010 Vol. 43 P. 182001

We analyze the kinematic dynamo in a conducting fluid where the stationary shear flow is accompanied by relatively weak random velocity fluctuations. The diffusionless and diffusion regimes are described. The growth rates of the magnetic field moments are related to the statistical characteristics of the flow describing the divergence of Lagrangian trajectories. A degree of ...

Added: February 5, 2017

Kolokolov I., Lebedev V., Balkovsky E. et al., JETP Letters 1995 Vol. 61 No. 12 P. 1049-1054

Advection of a passive scalar $\theta$ in $d=2$ by a large-scale velocity
field rapidly changing in time is considered. The Gaussian feature of the
passive scalar statistics in the convective interval was discovered in
\cite{95CFKLa}. Here we examine deviations from the Gaussianity: we obtain
analytically the simultaneous fourth-order correlation function of $\theta$.
Explicit expressions for fourth-order objects,
like $\langle(\theta_1-\theta_2)^4\rangle$ are ...

Added: March 27, 2017

Kolokolov I., Lebedev V., Chertkov M. et al., International Journal of Modern Physics B 1996 Vol. 10 No. 18-19 P. 2273-2309

The steady statistics of a passive scalar advected by a random two-dimensional flow of an incompressible fluid is described at scales less than the correlation length of the flow and larger than the diffusion scale. The probability distribution of the scalar is expressed via the probability distribution of the line stretching rate. The description of ...

Added: March 28, 2017

Kolokolov I., Lebedev V., Chertkov M., Physics of Fluids 2007 Vol. 19 P. 101703-1-101703-4

Passive scalar turbulence forced steadily is characterized by the velocity correlation scale L,
injection scale l, and diffusive scale rd. The scales are well separated if the diffusivity is small,
rdl ,L, and one normally says that effects of diffusion are confined to smaller scales, rrd.
However, if the velocity is single scale, one finds that a weak ...

Added: February 10, 2017

Kolokolov I., Lebedev V., Sizov G., Journal of Experimental and Theoretical Physics 2011 Vol. 140 No. 2 P. 387-400

We analyze magnetic kinematic dynamo in a conducting fluid where the stationary shear flow is accompanied by relatively weak random velocity fluctuations. The diffusionless and diffusion regimes are described. The growth rates of the magnetic field moments are related to the statistical characteristics of the flow describing divergence of the Lagrangian trajectories. The magnetic field ...

Added: February 2, 2017

Окубо Ю. undefined., Journal of Physics: Conference Series 2017 Vol. 804 No. 012036 P. 1-8

We investigate the existence and the orthogonality of the generalized Jack symmetric functions which play an important role in the AGT relations. We show their orthogonality by deforming them to the generalized Macdonald symmetric functions. ...

Added: October 26, 2017

Semenov A. G., Zaikin A. D., Physical Review B: Condensed Matter and Materials Physics 2013 Vol. 88 No. 5 P. 054505-1-054505-10

We investigate the effect of interacting quantum phase slips on persistent current and its fluctuations in ultrathin superconducting nanowires and nanorings pierced by the external magnetic flux. We derive the effective action for these systems and map the original problem onto an effective sine-Gordon theory on torus. We evaluate both the flux dependent persistent current ...

Added: February 9, 2015

Slunyaev A., Кокорина А. В., Water Waves, Springer 2019 P. 1-20

The issue of accounting of the wave breaking phenomenon in direct numerical simulations of oceanic waves is discussed. It is emphasized that this problem is crucial for the deterministic description of waves, and also for the dynamical calculation of extreme wave statistical characteristics, such as rogue wave height probability, asymmetry, etc. The conditions for accurate ...

Added: October 13, 2019

Marshakov A., Миронов А. Д., Морозов А. Ю., Journal of Geometry and Physics 2011 Vol. 61 P. 1203-1222

We present a summary of current knowledge about the AGT relations for conformal blocks with additional insertion of the simplest degenerate operator, and a special choice of the corresponding intermediate dimension, when the conformal blocks satisfy hypergeometric-type differential equations in position of the degenerate operator. A special attention is devoted to representation of conformal block ...

Added: February 28, 2013

Праздничных А. И., Glazov M., Ren L. et al., Physical Review B: Condensed Matter and Materials Physics 2021 Vol. 103 No. 8 P. 085302-1-085302-12

The exciton valley dynamics in van der Waals heterostructures with transition metal dichalcogenide monolayers is driven by the long-range exchange interaction between the electron and the hole in the exciton. It couples the states active in the opposite circular polarizations resulting in the longitudinal-transverse splitting of excitons propagating in the monolayer plane. Here we study ...

Added: March 5, 2021

Pelinovsky E., Didenkulova I., Rybkin A., Journal of Fluid Mechanics 2014 Vol. 748 P. 416-432

We present an exact analytical solution of the nonlinear shallow water theory for wave run-up in inclined channels of arbitrary cross-section, which generalizes previous studies on wave run-up for a plane beach and channels of parabolic cross-section. The solution is found using a hodograph-type transform, which extends the well-known Carrier–Greenspan transform for wave run-up on ...

Added: November 19, 2014

Pelinovsky E., Kurkin A. A., Kozelkov A. et al., European Journal of Mechanics - B/Fluids 2018 Vol. 72 P. 616-623

The paper presents results of numerical simulations of freely rising solid spheres in a viscous fluid. The
diameter of spheres was 5 mm, 7 mm, 10 mm, and 20 mm, and the corresponding Reynolds numbers
varies in the interval 1400 < Re < 10100. It has been found that the free rise path varies, as the
Galileo number ...

Added: October 21, 2018

Zhukov A., Shapiro D., Pogosov W. et al., Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 93 P. 063845

Superconducting circuits provide a new platform for study of nonstationary cavity QED phenomena. An example of such a phenomenon is the dynamical Lamb effect, which is the parametric excitation of an atom due to nonadiabatic modulation of its Lamb shift. This effect was initially introduced for a natural atom in a varying cavity, while we ...

Added: October 18, 2016

Budkov Y., Kolesnikov A., Polymer Science - Series C 2018 Vol. 60 No. Supplement 1 P. 148-159

Theoretical models of the conformational behavior of flexible polymer chains in mixed solvents enunciated in the world literature during the last decade are critically reviewed. Models describing different mechanisms of coil-to-globule transitions in a good solvent induced by cosolvent addition are highlighted. Special attention is given to the analysis of theoretical approaches to describing the ...

Added: November 30, 2018