Fluid flow and conjugate heat transfer in a matrix of surface-mounted cubes: A PANS study

Basara, Branislav

doi:10.1016/j.ijheatfluidflow.2014.10.012

Cited by 11 publications

(3 citation statements)

References 22 publications

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“…f k ¼ 1 corresponds to a URANS solution; f k ¼ 0 corresponds to a fully-resolved DNS solution, and for values between zero and one, the flow is partially resolved, while other turbulent structures are modelled (Ma et al (2011) The current study focuses on changes to the flow topology brought about by the numerical schemes used for the momentum equations. For the simulations with PANS equations, the second-order accurate AVL SMART (Sharp and Monotonic Algorithm for Realistic Transport) was used for the momentum equations (Pr zulj and Basara (2001), Pr zulj (2016), Basara (2004), Basara (2015a) and the references therein) in conjunction with MINMOD (MINimum MODulus) for the turbulence equations (also see Harten (1983), Sweby (1984)); while for the LES, a blend of 95% central differencing with 5% first-order upwind scheme (CDS) is used for the convective flux in the momentum equations. Pure central differencing scheme was used for the continuity equation.…”

Section: Numerical Formulationmentioning

confidence: 99%

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Rao

Minelli

Zhang

et al. 2018

Journal of Wind Engineering and Industrial Aerodynamics

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The near-wake flow topology of a ground transportation system (GTS) is investigated using partially-averaged Navier-Stokes (PANS) simulations at Re ¼ 2:7 Â 10 4. Recent numerical investigations for the GTS model using large eddy simulations (LES) showed an anti-symmetric flow topology (flow state II) in the vertical midplane compared to that observed in previous experimental studies (flow state I). The geometrical configuration of the GTS permits bi-stable behaviour, and the realisation of each of the two flow states, which are characterised by an asymmetrical flow topology, is achieved by varying the differencing scheme for the convective flux in the PANS simulations; AVL SMART schemes predict flow state I, while central differencing scheme (CDS) predicts flow state II. When the GTS model was placed away from the ground plane, the AVL SMART scheme fails to predict the flow asymmetry resulting in a pair of symmetrical vortices in the vertical midplane, while flow state II topology is observed when CDS is used. The switch from flow state I (II) to flow state II (I) is achieved by changing the numerical scheme from AVL SMART (CDS) to CDS (AVL SMART), with an intermediate transient-symmetric (TS) state being observed during the switching process. The numerical scheme in the PANS simulations thus plays a critical role in determining the initial flow topology in the near wake of the GTS.

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Section: Numerical Formulationmentioning

confidence: 99%

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Rao

Minelli

Zhang

et al. 2018

Journal of Wind Engineering and Industrial Aerodynamics

Self Cite

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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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“…Simplified cases of flow around buildings consisting of three-dimensional flow around cubes with in-line or staggered configurations have been extensively covered in the literature [1][2][3][4][5][6][7][8][9][10]. More complex geometries were also used to simulate real building outer profiles [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Effect of Local Grid Refinement on Performance of Scale-Resolving Models for Simulation of Complex External Flows

Cheikh

Elkhoury

2019

Aerospace

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Numerical simulations are crucial for fast and accurate estimations of the flow characteristics in many engineering applications such as atmospheric boundary layers around buildings, external aerodynamics around vehicles, and pollutant dispersion. In the simulation of flow over urban-like obstacles, it is crucial to accurately resolve the flow characteristics with reasonable computational cost. Therefore, Large Eddy Simulations on non-uniform grids are usually employed. However, an undesirable accumulation of energy at grid-refinement interfaces was observed in previous studies using non-uniform grids. This phenomenon induced oscillations in the spanwise velocity component, mainly on fine-to-coarse grid interfaces. In this study, the two challenging test cases of flow over urban-like cubes and flow over a 3-D circular cylinder were simulated using three different scale-resolving turbulence models. Simulations were performed on uniform coarse and fine grids on one hand, and a non-uniform grid on the other, to assess the effect of mesh density and mesh interfaces on the models’ performance. Overall, the proposed One-Equation Scale-Adaptive Simulation (One-Equation SAS) showed the least deviation from the experimental results in both tested cases and on all grid sizes and types when compared to the Shear Stress Transport-Improved Delayed Detached Eddy Simulation (IDDES) and the Algebraic Wall-Modeled Large Eddy Simulation (WMLES).

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Fluid flow and conjugate heat transfer in a matrix of surface-mounted cubes: A PANS study

Cited by 11 publications

References 22 publications

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Investigation of the near-wake flow topology of a simplified heavy vehicle using PANS simulations

Topographically Controlled Marangoni-Rayleigh-Bénard Convection in Liquid Metals

Effect of Local Grid Refinement on Performance of Scale-Resolving Models for Simulation of Complex External Flows

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