The effect of Reynolds numbers for unequal gap spacings on flow past three square cylinders arranged in-line

Ul-Islam, Shams; Abbasi, Waqas Sarwar; Khan, Asad

doi:10.1007/s40430-015-0468-4

Cited by 5 publications

(2 citation statements)

References 19 publications

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“…In such case the flow characteristics become different from those in the case of single spacing. This interesting feature of fluid structure interaction has also been investigated by many researchers [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Transition from steady to unsteady state flow around two inline cylinders under the effect of Reynolds numbers

Abbasi

Islam

2018

J Braz. Soc. Mech. Sci. Eng.

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Numerical computations are carried out to analyze the transition in flow states around two inline square cylinders under the effect of Reynolds numbers (Re). For this analysis, Re is varied from 1 to 110 at a fixed spacing ratio g = 3.5. The results are presented in the form of vorticity contours, streamline graphs, temporal histories of drag and lift coefficients and power spectrum of lift coefficients. Also the physical parameters like average drag coefficient, Strouhal number and the rootmean-square values of drag and lift coefficients are presented as a function of Re. Three different states of flow are found in this study by systematically varying Re: (a) steady state, (b) quasi-unsteady state, and (c) unsteady state. The points of separation and reattachment of shear layers depend on Re. This study shows that the values of physical parameters strongly depend on flow states and change their behavior when flow mode changes from one state to another. A significant reduction in the values of flow induced forces found due to the presence of two cylinders in the flow field when compared to single cylinder values. The results of the present study are also compared with the available data of other researchers and found to be in good agreement.

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Section: Introductionmentioning

confidence: 99%

Transition from steady to unsteady state flow around two inline cylinders under the effect of Reynolds numbers

Abbasi

Islam

2018

J Braz. Soc. Mech. Sci. Eng.

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“…They reported steady flow, nearly unsteady flow, sparse Karman vortex street, non-fully developed vortex street in single and double row by systematically increasing g. The authors also reported that g = 3 is critical spacing value. Islam et al [24] also numerically examined the effect of Reynolds numbers for unequal gap spacings on flow past three inline square cylinders using the lattice Boltzmann method. The authors found that (g 1 , g 2 ) = (3,4) and (4,3) are the critical gap spacing.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of different aspect ratios for flow past three inline rectangular cylinders

Islam

Manzoor

Ying

et al. 2018

J Braz. Soc. Mech. Sci. Eng.

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In this paper, numerical investigations are carried out to study the effect of aspect ratios (AR = length/height) for flow past three rectangular cylinders aligned inline at different gap spacings (g) using lattice Boltzmann method. The aspect ratio is varied between 0.25 and 3, gap spacing is taken in the range from 0.5 to 7 and the Reynolds number is fixed at 150. With the help of present numerical investigation, it is found that the variation of forces with different AR and g is governed by six distinct flow patterns: (1) shear layer reattachment flow; (2) steady flow; (3) quasi-steady flow; (4) strongly interactive vortex shedding flow; (5) two-row vortex street flow; and (6) critical flow pattern. It is observed that the development of vortices, interferences of the free shear layers and the wake vortices distribution of three cylinders play a vital role in the variation of shedding frequencies and fluid forces. Consequently, the cylinders placed at downstream usually experience serious fluctuating forces due to unsteady wakes generated by the upstream cylinders. Also, the upstream cylinder normally experiences larger mean drag force as compared to the downstream ones. The sudden jumps in mean drag coefficients and Strouhal numbers with their maximum and minimum values are identified, respectively. The upstream and middle cylinders force coefficients strongly affected due to critical aspect ratios at different fixed gap spacings. It is observed that the wake transition at early stages significantly changes by changing the aspect ratios for fixed gap spacings. The results also show that the middle and downstream cylinders experience negative drag force for some aspect ratios and gap spacings. Furthermore, the dependence of the critical gap spacing on the aspect ratios is also discussed.

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The time-mean aerodynamic force characteristics of two square cylinders arranged inline

Liu,

Jiang,

et al. 2023

J Braz. Soc. Mech. Sci. Eng.

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The effect of Reynolds numbers for unequal gap spacings on flow past three square cylinders arranged in-line

Cited by 5 publications

References 19 publications

Transition from steady to unsteady state flow around two inline cylinders under the effect of Reynolds numbers

Transition from steady to unsteady state flow around two inline cylinders under the effect of Reynolds numbers

Numerical investigation of different aspect ratios for flow past three inline rectangular cylinders

The time-mean aerodynamic force characteristics of two square cylinders arranged inline

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