An experimental study on flow over two finite wall-mounted square cylinders in a staggered arrangement

In the present study, confined flows around two square cylinders in staggered arrangement were numerically investigated. Cross-flow and streamwise center-to-center spacings of one- and three-cylinder diameters, respectively, were considered. Simulations were carried out at Reynolds numbers Re = 50,100,150 and 180, where the resulting wakes are laminar and periodic. Results indicate that the presence of the downstream cylinder tends to reduce the Strouhal number, amplitude and the time-averaged lift coefficient of the upstream cylinder relative to the single cylinder cases. Furthermore, the time variations of upstream cylinder’s lift coefficient behave similar to that of a single cylinder.

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Experimental study on convective boiling flow and heat transfer in a microgap enhanced with a staggered arrangement of nucleated micro-pin-fins

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2019.118653 ◽

2019 ◽

Vol 144 ◽

pp. 118653 ◽

Cited By ~ 7

Author(s):

Liang-Han Chien ◽

Wun-Rong Liao ◽

Mohammad Ghalambaz ◽

Wei-Mon Yan

Keyword(s):

Heat Transfer ◽

Experimental Study ◽

Convective Boiling ◽

Flow And Heat Transfer ◽

Pin Fins ◽

Staggered Arrangement ◽

Boiling Flow ◽

Micro Pin Fins

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FLOW INDUCED VIBRATION IN SQUARE CYLINDER OF VARIOUS ANGLES OF ATTACK

IIUM Engineering Journal ◽

10.31436/iiumej.v23i1.1804 ◽

2022 ◽

Vol 23 (1) ◽

pp. 358-369

Author(s):

Nur Ain Shafiza Ramzi ◽

Kee Quen Lee ◽

NUR AMIRA BALQIS MOHD ZAINURI ◽

HOOI SIANG KANG ◽

NOR’AZIZI OTHMAN ◽

...

Keyword(s):

Experimental Study ◽

Wind Speed ◽

Wind Tunnel ◽

Wind Engineering ◽

Kuala Lumpur ◽

Velocity Range ◽

Square Cylinder ◽

Flow Induced Vibration ◽

Rigid Cylinder ◽

Square Cylinders

An experimental study was carried out to identify the effect of angle of attack on flow-induced vibration (FIV) of square cylinders. The experiment was conducted at the Aeronautical and Wind Engineering Laboratory (AEROLAB), UTM Kuala Lumpur using a wind tunnel that was free from external wind conditions. A supporting structure was designed and fabricated to conduct this experiment. The importance of this support structure was to enable the rigid cylinder to suspend and vibrate freely upon excitation of wind speed. The results were analysed through the response of amplitude and frequency of the rigid cylinder over a velocity range of 0.5m/s to 4.0m/s. The results showed that for a square cylinder of ?=0°, vortex-induced vibration (VIV) occurred at low reduced velocity (UR) in range of 5 ? UR ? 10 and galloping occurred at higher reduced velocity which started at UR=15. A tranquil zone was found between VIV and galloping in the reduced velocity range of 10 ? UR ? 15. As for ?=22.5° and 45°, only VIV response was found at low reduced velocity in range of 4? UR ? 9. ABSTRAK: Satu kajian eksperimentasi telah dilakukan bagi mengenal pasti pengaruh sudut serangan oleh getaran cetusan-aliran (FIV) dalam silinder persegi. Eksperimen ini dijalankan di Makmal Kejuruteraan Aeronautika dan Angin (AEROLAB), UTM Kuala Lumpur dengan menggunakan terowong angin yang bebas dari pengaruh angin luar. Struktur sokongan telah direka dan difabrikasi bagi tujuan eksperimen ini. Ini penting bagi membolehkan silinder pegun tergantung dan bergetar dengan bebas semasa ujian kelajuan angin. Dapatan kajian dianalisis melalui tindak balas amplitud dan frekuensi silinder pegun pada kadar halaju 0.5m/s sehingga 4.0m/s. Hasil kajian menunjukkan bahawa bagi silinder persegi ? = 0 °, getaran pengaruh-vorteks (VIV) berlaku pada halaju rendah (UR) dalam julat 5 ? UR ? 10 dan getaran lebih teruk telah ketara berlaku pada kadar halaju berkurang iaitu bermula pada UR = 15. Zon tenang dijumpai antara VIV dan getaran teruk pada kadar halaju berkurang 10 ? UR ? 15. Adapun pada ? = 22.5° dan 45°, hanya tindak balas VIV dijumpai pada halaju rendah dalam kadar 4? UR ? 9.

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Wake-Wake Interactions for a Pair of Staggered Cylinders at Low Reynolds Number (Re = 100)

Volume 1A: Symposia, Part 2 ◽

10.1115/ajkfluids2015-01795 ◽

2015 ◽

Author(s):

Mohd. Raees ◽

Sudipto Sarkar

Keyword(s):

Reynolds Number ◽

Vortex Shedding ◽

Flow Problem ◽

Stream Velocity ◽

Angle Of Incidence ◽

Square Cylinders ◽

Wake Interactions ◽

Staggered Arrangement ◽

Pitch Ratio ◽

Flow Domain

Fluid flow around two square cylinders of equal size arranged in staggered configuration is investigated using Fluent. The centre-to-centre pitch ratio is considered to be constant (P/D = 2) and the angle of incidence is varying from 0° to 90°. This simulation is carried out at Reynolds number Re = 100 (Re= U∞D/v, where U∞ is the free stream velocity, D is side of both the square cylinders and v is the kinematic viscosity of fluid) which lies in the periodic vortex shedding regime. The geometry of the flow problem is developed using Gambit software, which also helps to impose the boundary conditions of the flow domain. In the present work, instantaneous vortex dynamics for the staggered arrangement are discussed thoroughly along with aerodynamics forces and Strouhal frequency (St). When compared with previously published results, it reveals that Fluent is capable to generate almost identical results at least for laminar periodic vortex shedding regime.

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The aeroacoustics of finite wall-mounted square cylinders

Journal of Fluid Mechanics ◽

10.1017/jfm.2017.682 ◽

2017 ◽

Vol 832 ◽

pp. 287-328 ◽

Cited By ~ 12

Author(s):

Ric Porteous ◽

Danielle J. Moreau ◽

Con J. Doolan

Keyword(s):

Boundary Layer ◽

Experimental Study ◽

Reynolds Number ◽

Wind Tunnel ◽

Three Dimensional ◽

Flow Structures ◽

Hot Wire ◽

Radiated Noise ◽

Aspect Ratios ◽

Square Cylinders

This paper presents the results of an experimental study that relates the flow structures in the wake of a square finite wall-mounted cylinder with the radiated noise. Acoustic and hot-wire measurements were taken in an anechoic wind tunnel. The cylinder was immersed in a near-zero-pressure gradient boundary layer whose thickness was 130 % of the cylinder width, $W$. Aspect ratios were in the range $0.29\leqslant L/W\leqslant 22.9$ (where $L$ is the cylinder span), and the Reynolds number, based on width, was $1.4\times 10^{4}$. Four shedding regimes were identified, namely R0 ($L/W<2$), RI ($2<L/W<10$), RII ($10<L/W<18$) and RIII ($L/W>18$), with each shedding regime displaying an additional acoustic tone as the aspect ratio was increased. At low aspect ratios (R0 and RI), downwash dominated the wake, creating a highly three-dimensional shedding environment with maximum downwash at $L/W\approx 7$. Looping vortex structures were visualised using a phase eduction technique. The principal core of the loops generated the most noise perpendicular to the cylinder. For higher aspect ratios in RII and RIII, the main noise producing structures consisted of a series of inclined vortex filaments, where the angle of inclination varied between vortex cells.

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