Información del autor
Autor Pinelli, Alfredo |
Documentos disponibles escritos por este autor (53)
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Pinelli, Alfredo ; Couzy, W. ; Deville, M. O. ; Benocci, C. | Society for Industrial and Applied Mathematics | 1996A new Chebyshev collocation algorithm is proposed for the iterative solution of advection-diffusion problems. The main features of the method lie in the original way in which a finite-difference preconditioner is built and in the fact that the s[...]texto impreso
Santiago, J. L. ; Dejoan, A. ; Martilli, A. ; Martín , F. ; Pinelli, Alfredo | 2007In this study, we propose to assess and compare the performance of LES and RANS methodologies for the simulation of pollutant dispersion in an urban environment by making use of field and wind tunnel measurements of the MUST experiment configura[...]texto impreso
Modern multi-core and many-core systems offer a very impressive cost/performance ratio. In this paper a set of new parallel implementations for the solution of linear systems with block-tridiagonal coefficient matrix on current parallel architec[...]texto impreso
Sekimoto, Atshushi ; Sekiyama, K. ; Kawahara, Genta ; Uhlmann, Markus ; Pinelli, Alfredo | Begell House | 2009Direct numerical simulations of fully developed low-Reynolds-number turbulent flow in a horizontal square duct heated from below are performed at Richardson numbers 0 ? Ri ? 1.03 to investigate the buoyancy effects on the coherent structures nea[...]texto impreso
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An original method to precondition Chebyshev collocated advection-diffusion operators is proposed. The preconditioner, based on an upwind finite difference approximation, is tested on one- and two-dimensional problems. The preconditioner behaves[...]texto impreso
The two-dimensional incompressible Navier-Stokes equations in primitive variables have been solved by a pseudospectral Chebyshev method using a semi-implicit fractional step scheme. The latter has been adapted to the particular features of spect[...]texto impreso
A new Chebyshev pseudo-spectral algorithm with finite difference preconditioning is proposed for the solution of advection-diffusion equations, A mapping technique is introduced which allows good convergence for any Peclet number both for one-di[...]texto impreso
Direct numerical simulation of fully developed 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[...]texto impreso
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The large-eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) methodologies are used to simulate the air flow inside the container's array geometry of the Mock Urban Setting Test (MUST) field experiment. Both tools are assessed and [...]texto impreso
Large-eddy simulations (LES) and Reynolds-averaged Navier-Stokes (RANS) computations of pollutant dispersion are reported for the Mock Urban Setting Test (MUST) field experiment flow. In particular we address the effects of incident wind angle d[...]texto impreso
Favier, J. ; Pinelli, Alfredo ; Piomelli, U. | Elsevier France-editions Scientifiques Medicales Elsevier | 2012The influence of spanwise geometrical undulations of the leading edge of an infinite wing is investigated numerically at low Reynolds number, in the context of passive separation control and focusing on the physical mechanisms involved. Inspired[...]texto impreso
We have conducted a DNS study of dilute turbulent particulate flow in a vertical plane channel, considering up to 8192 finite-size rigid particles with numerically resolved phase interfaces. The particle diameter corresponds to approximately 9 w[...]texto impreso
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Numerical experiments on modified turbulent channels are used to differentiate between possible turbulence generation mechanisms in wall bounded flows. It is shown that a regeneration cycle exists which is local to the near-wall region and does [...]texto impreso
We present a new method to capture the finite-size effects induced by particles transported by a fluid flow, with a low computational cost compared to available fully-resolved methods, thus allowing to tackle configurations with high volume frac[...]texto impreso
In Immersed Boundary Methods (IBM) the effect of complex geometries is introduced through the forces added in the Navier-Stokes solver at the grid points in the vicinity of the immersed boundaries. Most of the methods in the literature have been[...]texto impreso
We present an immersed-boundary algorithm for incompressible flows with complex boundaries, suitable for Cartesian or curvilinear grid system. The key stages of any immersed-boundary technique are the interpolation of a velocity field given on a[...]texto impreso
Revell, A. ; Favier, J. ; Pinelli, Alfredo | 2012This paper introduces the recent work undertaken on the development of a code based on the combination of the Lattice Boltzmann Method (LBM) with a recent version of the Immersed Boundary Method (IBM). The code is first validated against existin[...]texto impreso
Pinelli, Alfredo ; Benocci, C. | 1989The development of a code for the large eddy simulation of wall bounded turbulent shear layers is described. The numerical approach selected is a finite difference discretization of the filtered Navier-Stokes equations, where the unresolved part[...]texto impreso
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Kawahara, Genta ; Jiménez, J. ; Uhlmann, Markus ; Pinelli, Alfredo | 2003The linear inviscid instability of an infinitely thin vortex sheet, periodically corrugated with finite amplitude along the spanwise direction, is investigated analytically. Two types of corrugations are studied, one of which includes the presen[...]texto impreso
Kawahara, Genta ; Jiménez, Javier ; Uhlmann, Markus ; Pinelli, Alfredo | Cambridge University Press | 2003The linear inviscid instability of an infinitely thin vortex sheet, periodically corrugated with finite amplitude along the spanwise direction, is investigated analytically. Two types of corrugations are studied, one of which includes the presen[...]texto impreso
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[...]texto impreso
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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. [...]texto impreso
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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[...]texto impreso
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[...]texto impreso
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[...]texto impreso
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 [...]texto impreso
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[...]texto impreso
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[...]texto impreso
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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[...]texto impreso
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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[...]texto impreso
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Sanz, D. ; Muñoz, R. ; Armesto, L. ; Hontañón, E. ; Pinelli, Alfredo ; Espigares, M. M. | Elsevier | 2001texto impreso
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 [...]texto impreso
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[...]texto impreso
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[...]texto impreso
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 0texto impreso
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 [...]texto impreso
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[...]texto impreso
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[...]texto impreso
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 [...]texto impreso
Uhlmann, Markus ; Pinelli, Alfredo | 2003A two-dimensional model capable of simulating thermal convection flow in complex geometries has been implemented in a finite-difference setting and using a fictitious domain method of type “direct explicit forcing". The Boussinesq approximation [...]