Numerical simulation of Aspect ratio effect of the rectangular cylinder on the aerodynamic noise

Abbasi, Sarallah

doi:10.22061/jcarme.2022.7906.2056

Document Type : Research Paper

Author

Sarallah Abbasi

School of Mechanical Engineering, Arak University of Technology, Arak , Iran

https://doi.org/10.22061/jcarme.2022.7906.2056

Abstract

The purpose of this paper is to investigate the effect of aspect ratio on vortex on vortex shedding and transient flow induced noise over a rectangular cylinder is presented. The freestream velocity is assumed 50 m/s. URANS equations with turbulence model k-ω-SST are employed to flow analysis. Aerodynamic noise calculations are performed using FW-H analogy. The rectangular cross-section with various lengths and widths is considered. Comparison of the results extracted in the present study with the experimental results of other reference indicates the accuracy of the present research. In this study, the aspect ratios from 0.6 to 6 (equivalent to Reynolds numbers from 2.5×10^4 to 5.6×10^4) is studied. The simulations can be divided into two categories. In the first category, the ratio of length to width (R=B/H) is less than one, and in the second one, this ratio is greater than one. In the first case, noise is reduced by a relatively low slope. But in the second condition, the behavior of noise is different in various ratios and the slope of noise variations is high. The flow structure is also discussed in this paper. It is founded that for the first category, by increasing aspect ratio both the fluctuations and aerodynamic forces are reduced and the longitudinal wake zone is increased. But in the second category, fluctuations of flow may be increased or decreased in various aspect ratios.

Graphical Abstract

Keywords

References

[1] S. Mehryan, F.M. Kashkooli and M. Soltani, “Comprehensive study of the impacts of surrounding structures on the aero-dynamic performance and flow characteristics of an outdoor unit of split-type air conditioner”, Build. Simu., Vol. 11, No. 2 , pp. 325-337, (2018).

[2] A. Modir and N. Goudarzi, “Experimental investigation of Reynolds number and spring stiffness effects on vortex induced vibrations of a rigid circular cylinder”, Eur. J. Mech. B. Fluids., Vol. 74, pp. 34-40, (2019).

[3] N. Fujisawa, K. Hirabayashi and T. Yamagata, “Aerodynamic noise reduction of circular cylinder by longitudinal grooves”, J. Wind Eng. Ind. Aerodyn., Vol. 199, 104129, (2020).

[4] A. Sohankar, “Flow over a bluff body from moderate to high Reynolds numbers using large eddy simulation”, Comput. Fluids., Vol. 35, No. 10, pp. 1154-1168, (2006).

[5] G. Iaccarino, A. Ooi, P. Durbin and M. Behnia, “Reynolds averaged simulation of unsteady separated flow”, Int. J. Heat Fluid Flow., Vol. 24, No. 2, pp. 147-156, (2003).

[6] R. Davis, E. Moore and L. Purtell, “A numerical‐experimental study of confined flow around rectangular cylinders”, Phys. Fluids., Vol. 27, No. 1, pp. 46-59, (1984).

[7] F. Margnat, “Hybrid prediction of the aerodynamic noise radiated by a rectangular cylinder at incidence”, Comput. Fluids., Vol. 109, pp. 13-26, (2015).

[8] S. Abbasi and M. Souri, “On the passive control of aeroacoustics noise behind a square cylinder”, J. Braz. Soc. Mech. Sci. Eng.,Vol. 43, No. 2, pp. 1-16, (2021).

[9] P. Bearman and E. Obasaju, “An experimental study of pressure fluctuations on fixed and oscillating square-section cylinders”, J. Fluid Mech., Vol. 119, pp. 297-321, (1982).

[10] D.A. Lyn, S. Einav, W. Rodi and J.-H. Park, “A laser-Doppler velocimetry study of ensemble-averaged characteristics of the turbulent near wake of a square cylinder”, J. Fluid Mech., Vol. 304, pp. 285-319, (1995).

[11] N. Curle, “The influence of solid boundaries upon aerodynamic sound”, Proc. R. Soc. London, Ser. A., Vol. 231, No. 1187, pp. 505-514, (1955).

[12] H. Nakaguchi, “An experimental study on aerodynamic drag of rectangular cylinders”, J. Jpn. Soc. Aeronaut. Eng., Vol. 16, pp. 1-5, (1968).

[13] C. Norberg, “Flow around rectangular cylinders: pressure forces and wake frequencies”, J. Wind Eng. Ind. Aerodyn., Vol. 49, No. 1-3, pp. 187-196, (1993).

[14] Y. Ohya, “Note on a discontinuous change in wake pattern for a rectangular cylinder”, J. Fluids Struct., Vol. 8, No. 3, pp. 325-330, (1994).

[15] A. Okajima, “Numerical simulation of flow around rectangular cylinders”, J. Wind Eng. Ind. Aerodyn., 33, No. 1-2, pp. 171-180, (1990).

[16] K. Shimada and T. Ishihara, “Application of a modified k–ε model to the prediction of aerodynamic characteristics of rectangular cross-section cylinders”, J. Fluids Struct., Vol. 16, No. 4, pp. 465-485, (2002).

[17] A. Saha, G. Biswas and K. Muralidhar, “Influence of inlet shear on structure of wake behind a square cylinder”, J. Eng. Mech., Vol. 125, No. 3, pp. 359-363, (1999).

[18] A.K. Saha, K. Muralidhar and G. Biswas, “Vortex structures and kinetic energy budget in two-dimensional flow past a square cylinder”, Comput. Fluids., Vol. 29, No. 3, pp. 669-694, (2000).

[19] T. Tamura, “Accuracy of the very large computation for aerodynamic forces acting on a stationary or an oscillating cylinder-type structure”, IWEF Workshop on CFD for Prediction of Wind Loading on Buildings and Structures, pp. 2.1-2.22, (1995).

[20] S. Murakami and A. Mochida, “On turbulent vortex shedding flow past 2D square cylinder predicted by CFD”, J. Wind Eng. Ind. Aerodyn., Vol. 54, pp. 191-211, (1995).

[21] X. Tian, M.C. Ong, J. Yang and D. Myrhaug, “Unsteady RANS simulations of flow around rectangular cylinders with different aspect ratios”, Ocean Eng., Vol. 58, pp. 208-216, (2013).

[22] M. Ricci, L. Patruno, S. de Miranda and F. Ubertini, “Flow field around a 5: 1 rectangular cylinder using LES: Influence of inflow turbulence conditions, spanwise domain size and their interaction”, Comput. Fluids., Vol. 149, pp.181-193, (2017).

[23] J.F. Williams and D.L. Hawkings, “Sound generation by turbulence and surfaces in arbitrary motion”, Philos. Trans. R. Soc. London, Ser. A., Vol. 264, No. 1151,pp. 321-342, (1969).

[24] W.-T. Chong, W.K. Muzammil, K.-H. Wong, C.-T. Wang, M. Gwani, Y.-J. Chu and S.-C. Poh, “Cross axis wind turbine: Pushing the limit of wind turbine technology with complementary design”, Appl. Energy., Vol. 207, pp.78-95, (2017).

[25] P.C. Rocha, H.B. Rocha, F.M. Carneiro, M.V. da Silva and A.V. Bueno, “k–ω SST (shear stress transport) turbulence model calibration: A case study on a small scale horizontal axis wind turbine”, Energy.,Vol. 65, pp. 412-418, (2014).

[26] J. Zhang, W. Chu, H. Zhang, Y. Wu and X. Dong, “Numerical and experimental investigations of the unsteady aerodynamics and aero-acoustics characteristics of a backward curved blade centrifugal fan”, Appl. Acoustics, Vol. 110, pp. 256-267, (2016).

[27] R. Octavianty and M. Asai, “Effects of short splitter plates on vortex shedding and sound generation in flow past two side-by-side square cylinders”, Exp. Fluids., Vol. 57, No. 9, pp. 143, (2016).

[28] Y. Ohtsuki, “Wind tunnel experiments on aerodynamic forces and pressure distributions of rectangular cylinders in a uniform flow”, Proc. 5th Symp. on Wind effects on structures., pp. 169-175, (1978).

[29] H. Sakamoto, H. Haniu and Y. Kobayashi, “Fluctuating force acting on rectangular cylinders in uniform flow (on rectangular cylinders with fully separated flow) ”, Trans. Jpn. Soc. Mech. Eng. Ser.B., Vol. 55, No. 516, pp. 2310-2317, (1989).

[30] P. Bearman and D. Trueman, “An investigation of the flow around rectangular cylinders”, Aeronaut. Q., Vol. 23, No. 3, pp. 229-237, (1972).