Large-eddy simulation of turbulent flow and dispersion over a matrix of wall-mounted cubes

Saeedi, Mohammad; Wang, Bing-Chen

doi:10.1063/1.4935112

Cited by 16 publications

(2 citation statements)

References 47 publications

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“…Additional affinity can also be identified in the tendency of both categories of systems to develop turbulence or relatively chaotic solutions in some circumstances, i.e., large values of the Reynolds and Marangoni numbers, respectively (both account for the strength of horizontally directed flow). In the wind-obstacles problem, such complex states are essentially the outcome of purely hydrodynamic effects and related bifurcations [18,[42][43][44][45][46][47][48][49][50].We have shown that if hybrid buoyancy-Marangoni convection induced by hot blocks in liquid metals is considered, the frequency spectra still align with the Kolmogorov law in a certain range of frequencies.…”

Section: Discussionmentioning

confidence: 86%

Topographically Controlled Marangoni-Rayleigh-Bénard Convection in Liquid Metals

Lappa

Sayar

Waris

2021

Fluids

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Convection induced in a layer of liquid with a top free surface by a distribution of heating elements at the bottom can be seen as a variant of standard Marangoni–Rayleigh–Bénard Convection where in place of a flat boundary at constant temperature delimiting the system from below, the underlying thermal inhomogeneity reflects the existence of a topography. In the present work, this problem is investigated numerically through solution of the governing equations for mass, momentum and energy in their complete, three-dimensional time-dependent and non-linear form. Emphasis is given to a class of liquids for which thermal diffusion is expected to dominate over viscous effects (liquid metals). Fixing the Rayleigh and Marangoni number to 104 and 5 × 103, respectively, the sensitivity of the problem to the geometrical, kinematic and thermal boundary conditions is investigated parametrically by changing: the number and spacing of heating elements, their vertical extension, the nature of the lateral boundary (solid walls or periodic boundary) and the thermal behavior of the portions of bottom wall between adjoining elements (assumed to be either adiabatic or at the same temperature of the hot blocks). It is shown that, like the parent phenomena, this type of thermal flow is extremely sensitive to the specific conditions considered. The topography can be used to exert a control on the emerging flow in terms of temporal response and patterning behavior.

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Section: Discussionmentioning

confidence: 86%

Topographically Controlled Marangoni-Rayleigh-Bénard Convection in Liquid Metals

Lappa

Sayar

Waris

2021

Fluids

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“…Today, the choice to restrict to strongly idealized geometries like uniform buildings arrays is not so much motivated by cost considerations, as by advantages for the study of fundamental turbulence aspects and parameterizations that can be substantiated by a relative abundance of corresponding windtunnel measurements (e.g. Boppana et al, 2010;Gu et al, 2011;Inagaki et al 2012;Saeedi and Wang, 2015;Goodfriend et al 2016;Castro et al 2017;Llaguno-Munitxa et al, 2017). However, in order to investigate the full range of complex geometry-induced flow and dispersion patterns of real cities, studies have to be expanded to realistic, vertically and horizontally heterogeneous canopies (see for example comments on Kanda et al, 2013 and references therein).…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation study on the structure of turbulent flow in a complex city

Tolias

Koutsourakis

Hertwig

et al. 2018

Journal of Wind Engineering and Industrial Aerodynamics

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Large Eddy Simulation (LES) of atmospheric flows has become an increasingly popular modelling approach within the last years, as it has the potential to provide deeper insight into unsteady flow phenomena. LES can be improved and validated using specifically designed and well documented wind tunnel datasets. In this work, we evaluate the performance of LES against a wind tunnel experiment in a semi-idealized city ("Michel-Stadt"; CEDVAL-LES database) and use the LES results to study the structure of the turbulent flow at the particular urban area. The first, second and third order statistics are presented, as well as velocity frequency distributions and energy spectra. The results compare well with the experimental values. Information about special features of the flow field is also provided. A particular focus of this work is put on the influence of grid resolution on the results. Five different grids are examined and the required resolution for turbulent flow within the canopy layer is evaluated. This study reveals the strong potential of LES for urban flow simulations. It is shown that LES can assess highly non-Gaussian flow behaviour in street canyons, which has implications for urban ventilation, wind comfort assessment and urban design.

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The Influence of Spurious Periodicity on the Flow Characteristics of a Separated Turbulent Boundary Layer with and Without Active Flow Control

Asgari,

Saeedi

2024

Flow Turbulence Combust

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Large-eddy simulation of turbulent flow and dispersion over a matrix of wall-mounted cubes

Cited by 16 publications

References 47 publications

Topographically Controlled Marangoni-Rayleigh-Bénard Convection in Liquid Metals

Topographically Controlled Marangoni-Rayleigh-Bénard Convection in Liquid Metals

Large Eddy Simulation study on the structure of turbulent flow in a complex city

The Influence of Spurious Periodicity on the Flow Characteristics of a Separated Turbulent Boundary Layer with and Without Active Flow Control

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