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CONTENTS
Volume 34, Number 1, January 2022 (Special Issue)
 


Abstract
The international Benchmark on the Aerodynamics of a Rectangular 5:1 Cylinder (BARC) addresses the high Reynolds number, external, unsteady flow around a stationary, sharp-edged rectangular cylinder, and the associated aerodynamic actions (Bartoli et al. 2020). In spite of the simple geometry of the cylinder, BARC is a paradigmatic example of the intricate flows around elongated bodies having a low degree of bluffness, often encountered in Engineering design practice. BARC has been initially conceived as a double-blind benchmark, i.e., without a-priori selected reference measurements, and open to side-ground parametrical studies around the main setup. Thanks to such an approach, the benchmark attracted the attention of a number of researchers and practitioners adopting both numerical and experimental approaches in several academic and industrial sectors. More than 30 scientific papers on international journals have been devoted to BARC up to now. The present special issue follows some major milestones of the BARC past activities: the BARC launching on July 2008 at BBAA VI Conference; the BARC website online since 2009, hosted by the Italian Association of Wind Engineering (ANIV), and renewed on June 2020 (www.aniv-iawe.org/barc-home); the overview paper on BARC studies after the first four years of activity published on January 2014 (Bruno et al. 2014). Since May 2014 BARC enters as Silver content among the Underlying Flow Regimes (UFR_2-15) in the Knowledge Base Wiki of the European Research Community in Turbulence and Combustion (ERCOFTAC, Bruno & Salvetti, 2017). On February 2021 the BARC-MYOC (Make Your Own Comparison) web application is made available at the BARC website to collect, postprocess and compare the large amount of scientific results obtained so far (Bruno and Mannini 2021). On the one side, BARC is nowadays a mature test-bench for calibration of WT facilities, validation of CFD codes, training of the new generation of early stage researchers. On the other side, open issues still remain in the understanding and modelling of the BARC main flow, and towards new BARC-related problems. This special issue aims at gathering researchers from both Fluid Mechanics and Wind Engineering communities, promoting exchanges and complementary approaches between them, crossing the borders of contiguous, but sometimes shamefully apart, disciplinary fields. Both numerical and experimental approaches are deployed: the special issue collects 13 studies, carried out in equal part by wind tunnel tests and computational simulations. They effectively complement each other with respect to methods and applications. Computational studies span over a rich variety of approaches to turbulence, from DNS (Chiarini and Quadrio, Corsini et al.) to LES (Crivellini et al. Lunghi et al. Sakuma et al.) and RANS (Xu et al. Ma et al. Sakuma et al.), and over different numerical approaches. Experimental tests move from classical pressure and force measurements (Cárdenas-Rondón et al. Yang et al. Wang et al. Lei et al. Pasqualetto et al.) to Particle Image Velocimetry and other anemometric techniques (Guissart et al. Pasqualetto et al.). Beside the main setup, new problems are proposed and investigated. Among them, let us cite the 'rounded BARC' (Chiarini and Quadrio, Lunghi et al. Sakuma et al.), the 'porous BARC' (Xu et al.), the 'gust BARC' (Cardenas-Rondon et al. Yang et al.), the 'BARC at incidence' (Guissart et al. Cardenas-Rondon et al. Sakuma et a.), the 'oscillating BARC' (Wang et al. Lei et al.). All of them are paradigmatic setups of recurrent problems in wind engineering applications. BARC is come of age. This special issue is a turning point from past activities to future ones. Good winds to BARC!

Key Words


Address


Abstract
In this work the flow through a hollow porous 5:1 rectangular cylinder made of perforated plates is numerically investigated by means of 2D URANS based simulations. Two approaches are adopted to account for the porous surfaces: in the first one the pores are explicitly modeled, so providing a detailed representation of the flow. In the second one, the porous surfaces are modeled by means of pressure jumps, which allow to take into account the presence of pores without reproducing the flow details. Results obtained by using the two aforementioned techniques are compared aiming at evaluating differences and similarities, as well as identifying the main flow features which might cause discrepancies. Results show that, even in the case of pores remarkably smaller than the immersed body, their arrangement can lead to local mechanisms able to affect the global flow arrangement, so limiting the accuracy of pressure jumps based simulations. Despite that, time-averaged fields often show a reasonable agreement between the two approaches.

Key Words
porosity; porous bluff-body; porous surface; pressure jump

Address
Mao Xu: DICAM, University of Bologna, Bologna, Italy

Luca Patruno: DICAM, University of Bologna, Bologna, Italy

Yuan-Lung Lo: Department of Civil Engineering, National Taipei University of Technology, Taipei, Taiwan

Stefano de Miranda: DICAM, University of Bologna, Bologna, Italy

Francesco Ubertini: DICAM, University of Bologna, Bologna, Italy

Abstract
This work comes within the framework of the "Benchmark on the Aerodynamics of a Rectangular Cylinder" that investigates a rectangular cylinder of length-to-depth ratio equal to 5. The present study reports and discusses velocity fields acquired using planar Particle Image Velocitmetry for several angles of attack and Reynolds numbers. In particular, for a cylinder depth-based Reynolds number of 2x104 and zero incidence angle, the flow features along the lateral (parallel to the freestream) upper and lower surfaces of the cylinder are reported. Using first and second order statistics of the velocity field, the main flow features are discussed, especially the size and location of the time-averaged flow structures and the distribution of the Reynolds stresses. The variation of the flow features with the incidence is also studied considering angles of attack up to 6°. It is shown that the time-averaged flow is fully detached for incidence higher than 2°. For an angle of attack of 0°, the effects of the Reynolds number varying between 5x103 and 2x104 are investigated looking at flow statistics. It is shown that the time averaged location of the reattachment point and the shape and position of the time-averaged main vortex are mostly constant with the Reynolds number. However, the size of the inner region located below the time-averaged shear layer and just downstream the leading edge corner appears to be strongly dependent on the Reynolds number.

Key Words
BARC; PIV; incidence sensitivity; Reynolds sensitivity; 5:1 rectangular cylinder

Address
Amandine Guissart: Institute for Fluid Mechanics and Aerodynamics, Technische Universitat Darmstadt, Darmstadt
FlughafenstraBe 19, 64347 Darmstadt-Griesheim

Erik Elaek: Institute for Fluid Mechanics and Aerodynamics, Technische Universitat Darmstadt, Darmstadt
FlughafenstraBe 19, 64347 Darmstadt-Griesheim

Jeanette Hussong: Institute for Fluid Mechanics and Aerodynamics, Technische Universitat Darmstadt, Darmstadt
FlughafenstraBe 19, 64347 Darmstadt-Griesheim

Abstract
Following the BARC initiative, wind tunnel measurements have been performed on a 5:1 rectangular cylinder. Pressure distribution has been measured in several sections, checking the two-dimensionality of the flow around the model. Mean values compare well with previous data. These measurements have been processed using the standard Proper Orthogonal Decomposition (POD) and the snapshot POD to obtain phase-resolved cycles. This decomposition has been used to analyze the characteristics of the flow around the cylinder, in particular, the behavior of the recirculation bubble in the upper/lower surfaces. The effect of the angle of attack, the turbulence intensity and the Reynolds number has been studied. First and second modes extracted from POD have been found to be related to the reattachment of the flow in the upper surface. Increasing the angle of attack is related to a delay in the reattachment position, while an increase in turbulence intensity makes the reattachment point to move towards the windward face.

Key Words
BARC; POD; wind tunnel

Address
Juan A. Cardenas-Rondon: Instituto Universitario "Ignacio Da Riva" (IDR/UPM), Universidad Politecnica de Madrid,
Plaza Cardenal Cisneros, 3, E-28040, Madrid, Spain

Mikel Ogueta-Gutierrez: Instituto Universitario "Ignacio Da Riva" (IDR/UPM), Universidad Politecnica de Madrid,
Plaza Cardenal Cisneros, 3, E-28040, Madrid, Spain

Sebastian Franchini: Instituto Universitario "Ignacio Da Riva" (IDR/UPM), Universidad Politecnica de Madrid,
Plaza Cardenal Cisneros, 3, E-28040, Madrid, Spain

Omar Gomez-Ortega: Instituto Universitario "Ignacio Da Riva" (IDR/UPM), Universidad Politecnica de Madrid,
Plaza Cardenal Cisneros, 3, E-28040, Madrid, Spain

Abstract
The BARC flow is studied via Direct Numerical Simulation at a relatively low turbulent Reynolds number, with focus on the geometrical representation of the leading-edge (LE) corners. The study contributes to further our understanding of the discrepancies between existing numerical and experimental BARC data. In a first part, rounded LE corners with small curvature radii are considered. Results show that a small amount of rounding does not lead to abrupt changes of the mean fields, but that the effects increase with the curvature radius. The shear layer separates from the rounded LE at a lower angle, which reduces the size of the main recirculating region over the cylinder side. In contrast, the longitudinal size of the recirculating region behind the trailing edge (TE) increases, as the TE shear layer is accelerated. The effect of the curvature radii on the turbulent kinetic energy and on its production, dissipation and transport are addressed. The present results should be contrasted with the recent work of Rocchio et al. (2020), who found via implicit Large-Eddy Simulations at larger Reynolds numbers that even a small curvature radius leads to significant changes of the mean flow. In a second part, the LE corners are fully sharp and the exact analytical solution of the Stokes problem in the neighbourhood of the corners is used to locally restore the solution accuracy degraded by the singularity. Changes in the mean flow reveal that the analytical correction leads to streamlines that better follow the corners. The flow separates from the LE with a lower angle, resulting in a slightly smaller recirculating region. The corner-correction approach is valuable in general, and is expected to help developing high-quality numerical simulations at the high Reynolds numbers typical of the experiments with reasonable meshing requirements.

Key Words
BARC; DNS

Address
Alessandro Chiarini: Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano, via La Masa 34, 20156 Milano, Italy

Maurizio Quadrio: Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano, via La Masa 34, 20156 Milano, Italy

Abstract
In this work the numerical results of the flow around a 5:1 rectangular cylinder at Reynolds numbers 3 000 and 40 000, zero angle of attack and smooth incoming flow condition are presented. Implicit Large Eddy Simulations (ILES) have been performed with a high-order accurate spatial scheme and an implicit high-order accurate time integration method. The spatial approximation is based on a discontinuous Galerkin (dG) method, while the time integration exploits a linearly-implicit Rosenbrock-type Runge-Kutta scheme. The aim of this work is to show the feasibility of high-fidelity flow simulations with a moderate number of DOFs and large time step sizes. Moreover, the effect of different parameters, i.e., dimension of the computational domain, mesh type, grid resolution, boundary conditions, time step size and polynomial approximation, on the results accuracy is investigated. Our best dG result at Re=3 000 perfectly agrees with a reference DNS obtained using Nek5000 and about 40 times more degrees of freedom. The Re=40 000 computations, which are strongly under-resolved, show a reasonable correspondence with the experimental data of Mannini et al. (2017) and the LES of Zhang and Xu (2020).

Key Words
BARC benchmark; discontinuous Galerkin method; Implicit Large Eddy Simulation; (ILES); implicit time integration

Address
Andrea Crivellini: Department of Industrial Engineering and Mathematical Science, Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy

Alessandra Nigro: Department of Industrial Engineering and Mathematical Science, Marche Polytechnic University, Via Brecce Bianche 12, 60131 Ancona, Italy

Alessandro Colombo: Department of Engineering and Applied Sciences, Universita degli Studi di Bergamo, Viale Marconi 5, 24044 Dalmine, Italy

Antonio Ghidoni: Department of Mechanical and Industrial Engineering, Universita degli Studi di Brescia, Via Branze 38, 25121 Brescia, Italy

Gianmaria Noventa: Department of Mechanical and Industrial Engineering, Universita degli Studi di Brescia, Via Branze 38, 25121 Brescia, Italy

Andrea Cimarelli: Department of Engineering "Enzo Ferrari", Universita degli Studi di Modena e Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy

Abstract
This paper presents a study on amplitude-dependent self-excited aerodynamic forces of a 5:1 rectangular cylinder through free vibration wind tunnel test. The sectional model was spring-supported in a single degree of freedom (SDOF) in torsion, and it is found that the amplitude of the free vibration cylinder model was not divergent in the post-flutter stage and was instead of various stable amplitudes varying with the wind speed. The amplitude-dependent aerodynamic damping is determined using Hilbert Transform of response time histories at different wind speeds in a smooth flow. An approach is proposed to extract aerodynamic derivatives as nonlinear functions of the amplitude of torsional motion at various reduced wind speeds. The results show that the magnitude of A2*, which is related to the negative aerodynamic damping, increases with increasing wind speed but decreases with vibration amplitude, and the magnitude of A3* also increases with increasing wind speed but keeps stable with the changing amplitude. The amplitude-dependent aerodynamic derivatives derived from the tests can also be used to estimate the post-flutter response of 5:1 rectangular cylinders with different dynamic parameters via traditional flutter analysis.

Key Words
5:1 rectangular cylinder; aerodynamic derivatives; amplitude-dependence; post-flutter response; wind tunnel test

Address
Qi Wang: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, China

Bo Wu: Wind Engineering Key Laboratory of Sichuan Province, Chengdu, Sichuan, 610031, China

Hai-li Liao: Wind Engineering Key Laboratory of Sichuan Province, Chengdu, Sichuan, 610031, China

Hanyu Mei: Wind Engineering Key Laboratory of Sichuan Province, Chengdu, Sichuan, 610031, China


Abstract
To better understand the vortex-induced vibration (VIV) characteristics of a 5:1 rectangular cylinder, the distribution of aerodynamic force and the non-dimensional power spectral density (PSD) of fluctuating pressure on the side surface were studied in different VIV development stages, and their differences in the stationary state and vibration stages were analyzed. The spanwise and streamwise correlations of surface pressures were studied, and the flow field structure partitions on the side surface were defined based on the streamwise correlation analysis. The results show that the variation tendencies of mean and root mean square (RMS) pressure coefficients are similar in different VIV development stages. The RMS values during amplitude growth are larger than those at peak amplitude, and the smallest RMS values are observed in the stationary state. The spanwise correlation coefficients of aerodynamic lifts increase with increase of the peak amplitude. However, for the lock-in region, the maximum spanwise correlation coefficient for aerodynamic lifts occurs in the VIV rising stage rather than in the peak amplitude stage, probably due to the interaction of vortex shedding force (VSF) and self-excited force (SEF). The streamwise correlation results show that the demarcation point positions between the recirculation region and the main vortex region remain almost constant in different VIV development stages, and the reattachment points gradually move to the tailing edge with increasing amplitude. This study provides a reference to estimate the demarcation point and reattachment point positions through streamwise correlation and phase angle analysis from wind tunnel tests.

Key Words
5:1 rectangular cylinder; aerodynamic force; spanwise/streamwise correlation; vortex-induced vibration

Address
Yongfu Lei: Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu 610031, China

Yanguo Sun: 1)Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu 610031, China
2)Key Laboratory for Wind Engineering of Sichuan Province, Chengdu 610031, China

Tianyi Zhang: Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu 610031, China

Xiongwei Yang: Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu 610031, China

Mingshui Li: 1)Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu 610031, China
2)Key Laboratory for Wind Engineering of Sichuan Province, Chengdu 610031, China

Abstract
Numerical simulations are conducted to investigate the uniform flow (UF) and sinusoidal streamwise flow (SSF) over an oscillating 5:1 rectangular cylinder with harmonic heaving motion at initial angles of attack of

Key Words
sinusoidal streamwise flow; 5:1 rectangular cylinder; unsteady lift; flow field

Address
Ruwei Ma:1)Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China
2) School of Mechanics and Engineering Science, Shanghai University, Shanghai, 200444, China

Qiang Zhou:1)Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China 2)Key Laboratory for Wind Engineering of Sichuan Province, Chengdu, 610031, China

Peiyuan Wang: Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China

Yang Yang:1)Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China 2)Key Laboratory for Wind Engineering of Sichuan Province, Chengdu, 610031, China

Mingshui Li:1)Research Center for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China 2)Key Laboratory for Wind Engineering of Sichuan Province, Chengdu, 610031, China

Abstract
We experimentally investigate the high-Reynolds flow around a rectangular cylinder of aspect ratio 5:1. This configuration is the object of the international BARC benchmark. Wind tunnel tests have been carried out for the flow at zero angle of attack and a Reynolds number, based on the crossflow cylinder length and on the freestream velocity, equal, to 40 000. Velocity measurements are obtained by using hot-wire anemometry along 50 different cross-flow traverses on the cylinder side and in the near wake. Differential pressure measurements are acquired on multiple streamwise sections of the model. The obtained measurements are in a good agreement with the state-of-the-art experiments. For the first time among the several contributions to the BARC benchmark, detailed flow measurements are acquired in the region near the cylinder side and in the near-wake flow. The edges and the thickness of the shear layers detaching from the upstream edges are derived from velocity measurements. Furthermore, we compute the flow frequencies characterizing the roll-up of the shear layers, the evolution of vortical structures near the cylinder side and the vortex shedding in the wake.

Key Words
BARC benchmark; hot-wire anemometry; lateral and near-wake flow features; pressure measurements; windtunnel experiments

Address
Elena Pasqualetto: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Gianmarco Lunghi: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Benedetto Rocchio: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Alessandro Mariotti: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Maria Vittoria Salvetti: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy


Abstract
The high-Reynolds number flow around a rectangular cylinder, having streamwise to crossflow length ratio equal to 5 is analyzed in the present paper. The flow is characterized by shear-layer separation from the upstream edges. Vortical structures of different size form from the roll-up of these shear layers, move downstream and interact with the classical vortex shedding further downstream in the wake. The corresponding mean flow is characterized by a recirculation region along the lateral surface of the cylinder, ending by mean flow reattachment close to the trailing edge. The mean flow features on the cylinder side have been shown to be highly sensitive to set-up parameters both in numerical simulations and in experiments. The results of 21 Large Eddy Simulations (LES) are analyzed herein to highlight the impact of the lateral mean recirculation characteristics on the near-wake flow features and on some bulk quantities. The considered simulations have been carried out at Reynolds number Re=DU_

Key Words
BARC benchmark; bulk quantities; Large-Eddy Simulations; lateral and near-wake flow features

Address
Gianmarco Lunghi:Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Elena Pasqualetto: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Benedetto Rocchio: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Alessandro Mariotti: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

aria Vittoria Salvetti: Dipartimento di Ingegneria Civile e Industriale, Università di Pisa, Via G. Caruso, 8, 56122 Pisa, Italy

Abstract
In this work a multi-fidelity non-intrusive polynomial chaos (MF-NIPC) has been applied to a structural wind engineering problem in architectural design for the first time. In architectural design it is important to design structures that are safe in a range of wind directions and speeds. For this reason, the computational models used to design buildings and bridges must account for the uncertainties associated with the interaction between the structure and wind. In order to use the numerical simulations for the design, the numerical models must be validated by experimental data, and uncertainties contained in the experiments should also be taken into account. Uncertainty Quantification has been increasingly used for CFD simulations to consider such uncertainties. Typically, CFD simulations are computationally expensive, motivating the increased interest in multi-fidelity methods due to their ability to leverage limited data sets of high-fidelity data with evaluations of more computationally inexpensive models. Previously, the multi-fidelity framework has been applied to CFD simulations for the purposes of optimization, rather than for the statistical assessment of candidate design. In this paper MF-NIPC method is applied to flow around a rectangular 5:1 cylinder, which has been thoroughly investigated for architectural design. The purpose of UQ is validation of numerical simulation results with experimental data, therefore the radius of curvature of the rectangular cylinder corners and the angle of attack are considered to be random variables, which are known to contain uncertainties when wind tunnel tests are carried out. Computational Fluid Dynamics (CFD) simulations are solved by a solver that employs the Finite Element Method (FEM) for two turbulence modeling approaches of the incompressible Navier-Stokes equations: Unsteady Reynolds Averaged Navier Stokes (URANS) and the Large Eddy simulation (LES). The results of the uncertainty analysis with CFD are compared to experimental data in terms of time-averaged pressure coefficients and bulk parameters. In addition, the accuracy and efficiency of the multi-fidelity framework is demonstrated through a comparison with the results of the high fidelity model.

Key Words
bluff-body aerodynamics; multi-fidelity methods; polynomial chaos expansions; uncertainty quantification

Address
Mayu Sakuma: Department of Civil, Geo and Environmental Engineering, Technical University of Munich, Ar-cistraBe 21, 80333 Munchen, Germany

Nick Pepper: Department of Aeronautics, Imperial College London, London, England SW7 2AZ, United Kingdom

Suneth Warnakulasuriya: Department of Civil, Geo and Environmental Engineering, Technical University of Munich, Ar-cistraBe 21, 80333 München, Germany

Francesco Montomoli: Department of Aeronautics, Imperial College London, London, England SW7 2AZ, United Kingdom

Roland Wuch-ner: Department of Civil, Geo and Environmental Engineering, Technical University of Munich, Ar-cistraBe 21, 80333 Munchen, Germany

Kai-Uwe Bletzinger: Department of Civil, Geo and Environmental Engineering, Technical University of Munich, Ar-cistraBe 21, 80333 Munchen, Germany

Abstract
In this paper, the fluctuating lift and drag forces on 5:1 rectangular cylinders with two different geometric scales in three turbulent flow-fields are investigated. The study is particularly focused on understanding the influence of the ratio of turbulence integral length scale to structure characteristic dimension (the length scale ratio). The results show that both fluctuating lift and drag forces are influenced by the length scale ratio. For the model with the larger length scale ratio, the corresponding fluctuating force coefficient is larger, while the spanwise correlation is weaker. However, the degree of influence of the length scale ratio on the two fluctuating forces are different. Compared to the fluctuating drag, the fluctuating lift is more sensitive to the variation of the length scale ratio. It is also found through spectral analysis that for the fluctuating lift, the change of length scale ratio mainly leads to the variation in the low frequency part of the loading, while the fluctuating drag generally follows the quasi-steady theory in the low frequency, and the slope of the drag spectrum at high frequencies changes with the length scale ratio. Then based on the experimental data, two empirical formulas considering the influence of length scale ratio are proposed for determining the lift and drag aerodynamic admittances of a 5:1 rectangular cylinder. Furthermore, a simple relationship is established to correlate the turbulence parameter with the fluctuating force coefficient, which could be used to predict the fluctuating force on a 5:1 rectangular cylinder under different parameter conditions.

Key Words
5:1 rectangular cylinder; aerodynamic force; turbulent flow; wind tunnel test

Address
Yang Yang: 1)Research Centre for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China
2) Key Laboratory for Wind Engineering of Sichuan Province, Chengdu, 610031, China

Mingshui Li:1)Research Centre for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China
2) Key Laboratory for Wind Engineering of Sichuan Province, Chengdu, 610031, China

Xiongwei Yang: Research Centre for Wind Engineering, Southwest Jiaotong University, Chengdu, 610031, China

Abstract
The aerodynamics of blunt bodies with separation at the sharp corner of the leading edge and reattachment on the body side are particularly important in civil engineering applications. In recent years, a number of experimental and numerical studies have become available on the aerodynamics of a rectangular cylinder with chord-to-thickness ratio equal to 5 (BARC). Despite the interest in the topic, a widely accepted set of guidelines for grid generation about these blunt bodies is still missing. In this work a new, well resolved Direct Numerical Simulation (DNS) around the BARC body at Re=3000 is presented and its results compared to previous DNSs of the same case but with different numerical approaches and mesh. Despite the simulations use different numerical approaches, mesh and domain dimensions, the main discrepancies are ascribed to the different grid spacings employed. While a more rigorous analysis is envisaged, where the order of accuracy of the schemes are kept the same while grid spacings are varied alternately along each spatial direction, this represents a first attempt in the study of the influence of spatial resolution in the Direct Numerical Simulation of flows around elongated rectangular cylinders with sharp corners.

Key Words
BARC benchmark; Direct Numerical Simulation

Address
Roberto Corsini: DIEF, University of Modena and Reggio Emilia, 41125 Modena, Italy

Diego Angeli: DISMI, University of Modena and Reggio Emilia, 42122 Reggio Emilia, Italy

Enrico Stalio: DIEF, University of Modena and Reggio Emilia, 41125 Modena, Italy

Sergio Chibbaro: 1)Sorbonne Université, Institut Jean le Rond d


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