Disentangling the triadic interactions in Navier-Stokes equations

Sahoo, Ganapati; Biferale, Luca

doi:10.1140/epje/i2015-15114-4

Cited by 16 publications

(20 citation statements)

References 40 publications

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“…However, it could still be associated to injection or removal of energy from specific locations and scales. It has been shown both in MHD [56] and in hydrodynamic flows [57] that a selective filter of the triads carrying the energy throughout the inertial range, as well as the absence of resonant triads in the anisotropic case in the presence of rotation and stratification [58], may lead to the modulation of an inverse cascade in fully developed three-dimensional turbulence. It would be thus interesting to investigate the nature of the sign of the local energy dissipation obtained with the proxy proposed here also by the implementation of shell models [59,60].…”

Section: A a Proxy Of The Local Energy Transfer In Turbulencementioning

confidence: 99%

Sign Singularity of the Local Energy Transfer in Space Plasma Turbulence

et al. 2019

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2In weakly collisional space plasmas, the turbulent cascade provides most of the energy that is dissipated at small scales by various kinetic processes. Understanding the characteristics of such dissipative mechanisms requires the accurate knowledge of the fluctuations that make energy available for conversion at small scales, as different dissipation processes are triggered by fluctuations of a different nature. The scaling properties of different energy channels are estimated here using a proxy of the local energy transfer, based on the third-order moment scaling law for magnetohydrodynamic turbulence. In particular, the sign-singularity analysis was used to explore the scaling properties of the alternating positive-negative energy fluxes, thus providing information on the structure and topology of such fluxes for each of the different type of fluctuations. The results show the highly complex geometrical nature of the flux, and that the local contributions associated with energy and cross-helicity nonlinear transfer have similar scaling properties. Consequently, the fractal properties of current and vorticity structures are similar to those of the Alfvénic fluctuations. PACS numbers: 94.05.-a, 94.05.Lk, 95.30.Qd

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Section: A a Proxy Of The Local Energy Transfer In Turbulencementioning

confidence: 99%

Sign Singularity of the Local Energy Transfer in Space Plasma Turbulence

et al. 2019

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“…Owing to its aforementioned connection to nonlinear Navier-Stokes dynamics and its relevance to atmospheric physics (Lilly 1986), the effect of helicity has been studied in a variety of turbulent flows, including homogeneous isotropic turbulence (Chen et al 2003a,b;Kessar et al 2015;Stepanov et al 2015;Gledzer & Chkhetiani 2015;Sahoo & Biferale 2015;Alexakis 2017), rotating turbulence (Mininni & Pouquet 2010a,b) and the atmospheric boundary layer (Deusebio & Lindborg 2014). However, the dependence of β on the helicity of the external force has never been investigated analytically or numerically.…”

Section: Introductionmentioning

confidence: 99%

Effects of helicity on dissipation in homogeneous box turbulence

Linkmann

2018

J. Fluid Mech.

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The dimensionless dissipation coefficient β = εL/U 3 , where ε is the dissipation rate, U the root-mean-square velocity and L the characteristic scale of the largest flow structures, is an important characteristic of statistically stationary homogeneous turbulence. In studies of β, the external force is typically isotropic and large scale, and its helicity H f either zero or not measured. Here, we study the dependence of β on H f and find that it decreases β by up to 10% for both isotropic forces and shear flows. The numerical finding is supported by static and dynamical upper bound theory. Both show a relative reduction similar to the numerical results. That is, the qualitative and quantitative dependence of β on the helicity of the force is well captured by upper bound theory. Consequences for the value of the Kolmogorov constant and theoretical aspects of turbulence control and modelling are discussed in connection with the properties of the external force. In particular, the eddy viscosity in large eddy-simulations of homogeneous turbulence should be decreased by at least 10% in the case of strongly helical forcing.

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“…The nature of sticking of heavy atoms to clean surfaces has been intensively investigated using semiclassical perturbation theory [2,[18][19][20][21][22]. Hubbard and Miller [18] calculated the sticking probability for the HeW(110) and NeW(110) systems in the regime when the energy transfer from the surface is small.…”

Section: Introductionmentioning

confidence: 99%

“…Later, an improved theory has been presented in [20], which included the second order corrections to the angular distribution of the scattered particles. In their recent work, Sahoo and Pollak [21] employed a one-dimensional generalized Langevin equation and derived an analytic expression for the temperature-dependent energy loss. A combination with the multiple collision theory of Fan and Manson [22] allowed to determine the fraction of trapped particles after subsequent collisions (bounces) with the surface.…”

Section: Introductionmentioning

confidence: 99%

Microscopic modeling of gas-surface scattering: II. Application to argon atom adsorption on a platinum (111) surface

Filinov¹,

Bönitz²,

Loffhagen³

2018

Plasma Sources Sci. Technol.

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A new combination of first principle molecular dynamics (MD) simulations with a rate equation model presented in the preceding paper (paper I) is applied to analyze in detail the scattering of argon atoms from a platinum (111) surface. The combined model is based on a classification of all atom trajectories according to their energies into trapped, quasi-trapped and scattering states. The number of particles in each of the three classes obeys coupled rate equations. The coefficients in the rate equations are the transition probabilities between these states which are obtained from MD simulations. While these rates are generally time-dependent, after a characteristic time scale t E of several tens of picoseconds they become stationary allowing for a rather simple analysis. Here, we investigate this time scale by analyzing in detail the temporal evolution of the energy distribution functions of the adsorbate atoms. We separately study the energy loss distribution function of the atoms and the distribution function of in-plane and perpendicular energy components. Further, we compute the sticking probability of argon atoms as a function of incident energy, angle and lattice temperature. Our model is important for plasma-surface modeling as it allows to extend accurate simulations to longer time scales.

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Disentangling the triadic interactions in Navier-Stokes equations

Cited by 16 publications

References 40 publications

Sign Singularity of the Local Energy Transfer in Space Plasma Turbulence

Sign Singularity of the Local Energy Transfer in Space Plasma Turbulence

Effects of helicity on dissipation in homogeneous box turbulence

Microscopic modeling of gas-surface scattering: II. Application to argon atom adsorption on a platinum (111) surface

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