نتایج جستجو برای: fully developed flow

تعداد نتایج: 1390984  

Journal: :Journal of Thermal Engineering 2021

We represent a conceptual scrutiny for completely organized convective heat transfer ring within the circular pipeline with power law liquids by means of realizing that diffusivity has been temperature gradient. The investigative resolution is availed and behaviour inspected under persistent thermic flux frontier condition. It demonstrated Nu stubbornly relies upon power-law index n value. (Nus...

Journal: :Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics 1999
G Boffetta A Celani A Crisanti A Vulpiani

The Lagrangian statistics of relative dispersion in fully developed turbulence is numerically investigated. A scaling range spanning many decades is achieved by generating a two-dimensional velocity field by means of a stochastic process with prescribed statistics and of a dynamical model (shell model) with fluctuating characteristic times. When the velocity field obeys Kolmogorov similarity, t...

Journal: :Physical review letters 2013
Cristian C Lalescu Charles Meneveau Gregory L Eyink

We investigate chaos synchronization of small-scale motions in the three-dimensional turbulent energy cascade, via pseudospectral simulations of the incompressible Navier-Stokes equations. The modes of the turbulent velocity field below about 20 Kolmogorov dissipation lengths are found to be slaved to the chaotic dynamics of larger-scale modes. The dynamics of all dissipation-range modes can be...

ژورنال: :مکانیک سازه ها و شاره ها 2012
محمد کلته عباس عباسی مجید بهرامی

in this paper, a novel approximate solution to determine the nusselt number for thermally developed, slug (low-prandtl), laminar, single phase flow in channels of arbitrary cross section is presented. using the saint-venant principle in torsion of beams, it is shown that the thermally developed nusselt number for low-prandtl flow is only a function of the geometrical parameters of the channel c...

2009
Luca Biferale

We review the Parisi-Frisch [1] MultiFractal formalism for Navier– Stokes turbulence with particular emphasis on the issue of statistical fluctuations of the dissipative scale. We do it for both Eulerian and Lagrangian Turbulence. We also show new results concerning the application of the formalism to the case of Shell Models for turbulence. The latter case will allow us to discuss the issue of...

2004
Eric D. Siggia

Kolmogorov's phenomenological theory for the energy spectrum in a turbulent fluid in three dimensions is perhaps the single most successful theoretical attempt to comprehend fully developed turbulence. (1) Nevertheless it fails to account for certain fluctuation effects (" intermittency ") that are seen experimentally in three dimensions3 2) Furthermore, it is formulated in such general terms t...

2016
Pouya Manshour Mehrnaz Anvari Nico Reinke Muhammad Sahim M. Reza Rahimi Tabar

Emergent extreme events are a key characteristic of complex dynamical systems. The main tool for detailed and deep understanding of their stochastic dynamics is the statistics of time intervals of extreme events. Analyzing extensive experimental data, we demonstrate that for the velocity time series of fully-developed turbulent flows, generated by (i) a regular grid; (ii) a cylinder; (iii) a fr...

2008
Christian Beck

The statistical properties of fully developed hydrodynamic turbulence can be successfully described using methods from nonextensive statistical mechanics. The predicted probability densities and scaling exponents precisely coincide with what is measured in various turbulence experiments. As a dynamical basis for nonextensive behaviour we consider nonlinear Langevin equations with fluctuating fr...

2005
M. Bahrami M. M. Yovanovich J. R. Culham

Pressure drop of fully developed, laminar, incompressible flow in smooth mini and microchannels of arbitrary cross-section is investigated. A compact approximate model is proposed that predicts the pressure drop for a wide variety of shapes. The model is only a function of geometrical parameters of the cross-section, i.e., area, perimeter, and polar moment of inertia. The proposed model is comp...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1997
G I Barenblatt A J Chorin V M Prostokishin

We compare mean velocity profiles measured in turbulent pipe flows (and also in boundary layer flows) with the predictions of a recently proposed scaling law; in particular, we examine the results of the Princeton "super-pipe" experiment and assess their range of validity.

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