Effect of the domain spanwise periodic length on the flow around a circular cylinder

Gioria, Rafael dos Santos; Meneghini, Júlio Romano; Aranha, José Augusto Penteado; Barbeiro, Iago de Carvalho; Carmo, Bruno Souza

doi:10.1016/j.jfluidstructs.2011.03.007

Cited by 12 publications

(7 citation statements)

References 10 publications

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“…They are significantly smaller than the results for infinite cylinders, ranging from approximately 0.08 for L/d 3 to 0.13 for L/d 20. Qu et al (2013) and Gioria et al (2011) It should be noted that Qu et al (2013) also performed numerical simulations for infinite cylinders, and that the values of St BvK they found were in remarkable agreement with the model of Williamson & Brown (1998). For the same Re d , the Strouhal number values they computed were thus lower for cylinders of fixed spanwise length.…”

Section: Wake Visualization and Analysissupporting

confidence: 56%

Kinematics and wake of freely falling cylinders at moderate Reynolds numbers

2019

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We investigated experimentally the motion of elongated finite-length cylinders (length $L$, diameter $d$) freely falling under the effect of buoyancy in a low-viscosity fluid otherwise at rest. For cylinders with densities $\unicode[STIX]{x1D70C}_{c}$ close to the density $\unicode[STIX]{x1D70C}_{f}$ of the fluid ($\overline{\unicode[STIX]{x1D70C}}=\unicode[STIX]{x1D70C}_{c}/\unicode[STIX]{x1D70C}_{f}\simeq 1.16$), we explored the effect of the body volume by varying the Archimedes number $Ar$ (based on the body equivalent diameter) between 200 and 1100, as well as the effect of their length-to-diameter ratios $L/d$ ranging from 2 to 20. A shadowgraphy technique involving two cameras mounted on a travelling cart was used to track the cylinders along their fall over a distance longer than $30L$. A dedicated image processing algorithm was further implemented to properly reconstruct the position and orientation of the cylinders in the three-dimensional space. In the range of parameters explored, we identified three main types of paths, matching regimes known to exist for three-dimensional bodies (short-length cylinders, disks and spheres). Two of these are stationary, namely, the rectilinear motion and the large-amplitude oscillatory motion (also referred to as fluttering or zigzag motion), and their characterization is the focus of the present paper. Furthermore, in the transitional region between these two regimes, we observed irregular low-amplitude oscillatory motions, that may be assimilated to the A-regimes or quasi-vertical regimes of the literature. Flow visualization using dye released from the bodies uncovered the existence of different types of vortex shedding in the wake of the cylinders, according to the style of path. The detailed analysis of the body kinematics in the fluttering regime brought to light a series of remarkable properties. In particular, when normalized with the characteristic velocity scale $u_{0}=\sqrt{(\overline{\unicode[STIX]{x1D70C}}-1)gd}$ and the characteristic length scale $l_{0}=\sqrt{dL}$, the mean vertical velocity $\overline{u_{Z}}$ and the frequency $f$ of the oscillations become almost independent of $L/d$ and $Ar$. The use of the length scale $l_{0}$ and of the gravitational velocity scale to build the Strouhal number $St^{\ast }=fl_{0}/u_{0}$ allowed us to generalize to short ($0.1\leqslant L/d\leqslant 0.5$) and elongated cylinders ($2\leqslant L/d\leqslant 12$), the result $St^{\ast }\simeq 0.1$. An interpretation of $l_{0}$ as a characteristic length scale associated with the oscillatory recirculation thickness generated near the body ends is proposed. In addition, the rotation rate of the cylinders scales with $u_{0}/L$, for all $L/d$ and $Ar$ investigated. Furthermore, the phase difference between the oscillations of the velocity component $u$ along the cylinder axis and of the inclination angle $\unicode[STIX]{x1D703}$ of the cylinder is approximately constant, whatever the elongation ratio $L/d$ and the Archimedes number $Ar$.

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Section: Wake Visualization and Analysissupporting

confidence: 56%

Kinematics and wake of freely falling cylinders at moderate Reynolds numbers

2019

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“…For realizability of a 3-D simulation of this canonical flow case, the spanwise dimension of the cylinder, the spanwise length L z , should be long enough to be able to capture the essentials of the anticipated large-scale 3-D spanwise flow developments (Gioria et al, 2011).…”

Section: Preliminaries and Global Resultsmentioning

confidence: 99%

Quantitative numerical analysis of flow past a circular cylinder at Reynolds number between 50 and 200

Norberg

Davidson

et al. 2013

Journal of Fluids and Structures

147

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Notice: Changes introduced as a result of publishing processes such as copy-editing and formatting may not be reflected in this document. For a definitive version of this work, please refer to the published source. Please note that access to the published version might require a subscription. Chalmers Publication Library (CPL) offers the possibility of retrieving research publications produced at Chalmers University of Technology. It covers all types of publications: articles, dissertations, licentiate theses, masters theses, conference papers, reports etc. Since 2006 it is the official tool for Chalmers official publication statistics. To ensure that Chalmers research results are disseminated as widely as possible, an Open Access Policy has been adopted. The CPL service is administrated and maintained by Chalmers Library.

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“…Gioria et al. (2011) investigated the effects of computational domain size in the spanwise direction on the flow around a circular cylinder at and reported that the three-dimensional flow can be reasonably represented if exceeds 6 diameters. In this study, the length-to-diameter ratio of the cylinder is 6.4.…”

Section: Methodsmentioning

confidence: 99%

“…It was reported that a cylinder length of 2D is enough for accurately predicting the fluid forces at Re = 1000 (Lei, Cheng & Kavanagh 2001). Gioria et al (2011) investigated the effects of computational domain size in the spanwise direction on the flow around a circular cylinder at Re = 400 and reported that the three-dimensional flow can be reasonably represented if L exceeds 6 diameters. In this study, the length-to-diameter ratio of the cylinder is 6.4.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of wake flow regimes behind a high-speed rotating circular cylinder in steady flow

Munir

Zhao

et al. 2019

J. Fluid Mech.

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Flow around a high-speed rotating circular cylinder for $Re\leqslant 500$ is investigated numerically. The Reynolds number is defined as $UD/\unicode[STIX]{x1D708}$ with $U$, $D$ and $\unicode[STIX]{x1D708}$ being the free-stream flow velocity, the diameter of the cylinder and the kinematic viscosity of the fluid, respectively. The aim of this study is to investigate the effect of a high rotation rate on the wake flow for a range of Reynolds numbers. Simulations are performed for Reynolds numbers of 100, 150, 200, 250 and 500 and a wide range of rotation rates from 1.6 to 6 with an increment of 0.2. Rotation rate is the ratio of the rotational speed of the cylinder surface to the incoming fluid velocity. A systematic study is performed to investigate the effect of rotation rate on the flow transition to different flow regimes. It is found that there is a transition from a two-dimensional vortex shedding mode to no vortex shedding mode when the rotation rate is increased beyond a critical value for Reynolds numbers between 100 and 200. Further increase in rotation rate results in a transition to three-dimensional flow which is characterized by the presence of finger-shaped (FV) vortices that elongate in the wake of the cylinder and very weak ring-shaped vortices (RV) that wrap the surface of the cylinder. The no vortex shedding mode is not observed at Reynolds numbers greater than or equal to 250 since the flow remains three-dimensional. As the rotation rate is increased further, the occurrence frequency and size of the ring-shaped vortices increases and the flow is dominated by RVs. The RVs become bigger in size and the flow becomes chaotic with increasing rotation rate. A detailed analysis of the flow structures shows that the vortices always exist in pairs and the strength of separated shear layers increases with the increase of rotation rate. A map of flow regimes on a plane of Reynolds number and rotation rate is presented.

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Effect of the domain spanwise periodic length on the flow around a circular cylinder

Cited by 12 publications

References 10 publications

Kinematics and wake of freely falling cylinders at moderate Reynolds numbers

Kinematics and wake of freely falling cylinders at moderate Reynolds numbers

Quantitative numerical analysis of flow past a circular cylinder at Reynolds number between 50 and 200

Numerical investigation of wake flow regimes behind a high-speed rotating circular cylinder in steady flow

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