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Autor Pinelli, Alfredo |
Documentos disponibles escritos por este autor (53)
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Uhlmann, Markus ; Pinelli, Alfredo ; Kawahara, Genta ; Sekimoto, Atshushi | Cambridge University Press | 2007A direct numerical simulation of turbulent flow in a straight square duct was performed in order to determine the minimal requirements for self-sustaining turbulence. It was found that turbulence can be maintained for values of the bulk Reynold[...]![]()
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The idea is based on identifying the physical roles of the solid and fluid stress tensors in the solid phase momentum equation. The tensors are reformulated as a sum of different terms. A comparison with the closure proposed by Marchioro et al. [...]![]()
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Pinelli, Alfredo ; Benocci, C. ; Deville, M. | 1992An original method for preconditioning Chebyshev collocated advection-diffusion operators is proposed. The preconditioner, based on an upwind finite difference approximation, is tested on one and two dimensional problems with both Neumann and Di[...]![]()
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Pinelli, Alfredo ; Uhlmann, Markus ; Sekimoto, Atshushi ; Kawahara, Genta | Cambridge University Press | 2010We have performed direct numerical simulations of turbulent flows in a square duct considering a range of Reynolds numbers spanning from a marginal state up to fully developed turbulent states at low Reynolds numbers. The main motivation stems f[...]![]()
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The primitive variable formulation of the unsteady incompressible Navier-Stokes equations in three space dimensions is discretized with a combined Fourier-Legendre spectral method. A semi-implicit pressure correction scheme is applied to decoupl[...]![]()
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Numerical experiments on modified turbulent channels at moderate Reynolds numbers are used to differentiate between several possible regeneration cycles for the turbulent fluctuations in wall-bounded flows. It is shown that a cycle exists which [...]![]()
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The near-wall region is the only place in zero-pressure-gradient boundary layer where the production of turbulent energy exceeds dissipation. The excess energy helps maintain turbulence in the core region, where the opposite is true. It is shown[...]![]()
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The appearance of secondary flow of Prandtl’s second kind is a well-known phenomenon in fully developed turbulent rectangular duct flow. The intensity of the secondary flow is two orders of magnitude smaller than that of the mean streamwise velo[...]![]()
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Kawahara, Genta ; Jiménez, J. ; Uhlmann, Markus ; Pinelli, Alfredo | Japan Society of Mechanical Engineers | 2000The linear stability analysis has been performed at Re.TAU.=180 for a turbulent-channel-type base flow with a periodic undulation in the spanwise direction in order to elucidate the generation mechanism of streamwise vorticity through the instab[...]![]()
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The near-wall region is characterized by the presence of organized structures [1], but the way in which they interact to maintain the local dynamics and to extract energy from the mean flow is still controversial. The two dominant structures are[...]![]()
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Sanz, D. ; Muñoz, R. ; Armesto, L. ; Hontañón, E. ; Pinelli, Alfredo ; Espigares, M. M. | Elsevier | 2001![]()
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Nowadays, the most used techniques to design dense gas-solid flow reactors rely upon numerical predictions obtained from hydrodynamic models, usually derived through some averaging processes of the complete conservation equations. The averaging [...]![]()
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We present numerically determined travelling-wave solutions for pressure-driven flow through a straight duct with a square cross-section. This family of solutions represents typical coherent structures (a staggered array of counter-rotating stre[...]![]()
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Isothermal, incompressible flow in a straight duct with square cross-section is known to be linearly stable [1]. Direct numerical simulation, on the other hand, has revealed that turbulence in this geometry is self-sustained above a Reynolds num[...]![]()
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Sekimoto, Atshushi ; Kawahara, Genta ; Sekiyama, K. ; Uhlmann, Markus ; Pinelli, Alfredo | American Institute of Physics | 2011Direct numerical simulations of fully developed turbulent flows in a horizontal square duct heated from below are performed at bulk Reynolds numbers Re(b) = 3000 and 4400 (based on duct width H) and bulk Richardson numbers 0![]()
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García Ybarra, P. L. ; Pinelli, Alfredo | Elsevier France-editions Scientifiques Medicales Elsevier | 2006The transport of a passive scalar within a turbulent plane channel flow has been theoretically analyzed by assuming that the Schmidt number Sc, associated to the molecular diffusivity of the passive scalar, is a large parameter. Throughout most [...]![]()
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Jiménez, J. ; Uhlmann, Markus ; Kawahara, Genta ; Pinelli, Alfredo | American Physical Society | 1999We have investigated a fully turbulent, low-Reynolds number plane channel with one impermeable and one porous wall. The latter is assumed to obey Darcy's law and to be mass-neutral in the mean. Our DNS data show an enhancement of wall friction u[...]![]()
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Direct numerical simulations of streamwise-localized turbulent flow (turbulent puff) in a horizontal square duct heated from above are performed at Richardson numbers 0 ? Ri ? 0.58 to characterize differences between isothermal and non-isotherma[...]![]()
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Jiménez, J. ; Uhlmann, Markus ; Pinelli, Alfredo ; Kawahara, Genta | Cambridge University Press | 2001The behaviour of turbulent shear flow over a mass-neutral permeable wall is studied numerically. The transpiration is assumed to be proportional to the local pressure fluctuations. It is first shown that the friction coefficient increases by up [...]