Abstract
Wind tunnel experiments were performed to study the effect of passive flow control strategies on the wake and drag of a semicircular cylinder of infinite aspect ratio. High-resolution planar particle image velocimetry was used to obtain flow statistics around the semicircular cylinder at Reynolds number \(Re\approx 3.2\times 10^4\) based on the cylinder diameter. The control mechanisms under consideration include rigid flaps of various lengths placed at the edges of the structure and a small slot along the symmetry plane of the cylinder. Mean velocity fields reveal the distinctive effects of each passive mechanism on the flow, such as velocity recovery, size of the recirculation bubble and location of the reattachment point. The distributions of turbulence kinetic energy and kinematic shear stress show the modulation of each passive control mechanism on the wake, including the onset and location of the maximum turbulence levels. Instantaneous and mean fields of swirling strength further highlight the role of the passive mechanisms in the vortex dynamics. Drag coefficient for the various cases was estimated indirectly from the flow measurements using a momentum balance. This approach shows that long flaps and slot were able to reduce drag with respect to the base case. The rigid flaps with length coincident with the diameter of the cylinder offered the best performance with drag reduction of \(\sim\)25\(\%\).
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References
Adrian RJ, Meinhart CD, Tomkins CD (2000) Vortex organization in the outer region of the turbulent boundary layer. J Fluid Mech 422:1–54
Adrian RJ, Christensen KT, Liu ZC (2000) Analysis and interpretation of instantaneous turbulent velocity fields. Exp Fluids 29:275–290
Antonia RA, Rajagopalan S (1990) Determination of drag of a circular cylinder. AIAA J 28(10):1833–1834
Baek H, Karniadakis GE (2009) Suppressing vortex-induced vibrations via passive means. J Fluid Struct 25:848–866
Chen WL, Gao DL, Yuan WY, Li H, Hu H (2015) Passive jet control of flow around a circular cylinder. Exp Fluids 56(11):1–15
Chen WL, Wang X, Xu F, Li H, Hu H (2016) Passive jet flow control method for suppressing unsteady vortex shedding from a circular cylinder. J Aerospace Eng 30(1):04016063. doi:10.1061/(ASCE)AS.1943-5525.0000661
Chen W-L, Xin DB, Xu F, Li H, Ou J-P, Hu H (2013) Suppression of vortex-induced vibration of a circular cylinder using suction-based flow control. J Fluid Struct 42:25–39
Choi H, Jeon W-P, Kim J (2008) Control of flow over a bluff body. Annu Rev Fluid Mech 40:113–139
Farhadi M, Sedighi K, Fattahi E (2010) Effect of a splitter plate on flow over a semi-circular cylinder. Proc IME G J Aeros Eng 224(3):321–330
Schlichting H (1979) Boundary layer theory. McGraw-Hill Book Company, New York
Hucho WH, Sovran G (1993) Aerodynamics of road vehicles. Annu Rev Fluid Mech 25(1):485–537
Hwang J-Y, Yang K-S (2007) Drag reduction on a circular cylinder using dual detached splitter plates. J Wind Eng Ind Aerodyn 95:551–564
Koike M, Nagayoshi T, Hamamoto N (2004) Research on aerodynamic drag reduction by vortex generators. Mitshubishi Motors Tech Rev. 2004
Kunze S, Brucker C (2012) Control of vortex shedding on a circular cylinder using self-adaptive hairy-flaps. C R Mec 340(1):41–56
Lien FS, Yee E, Cheng Y (2004) Simulation of mean flow and turbulence over a 2d building array using high-resolution cfd and a distributed drag force approach. J Wind Eng Ind Aerod 92(2):117–158
Lin J-C, Towfighi J, Rockwell D (1995) Instantaneous structure of the near-wake of a circular cylinder: on the effect of reynolds number. J Fluid Struct 9(4):409–418
Lin N, Letchford C, Tamura Y, Liang B, Nakamura O (2005) Characteristics of wind forces acting on tall buildings. J Wind Eng Ind Aerod 93(3):217–242
Mimeau C, Mortazavi I, Cottet GH (2014) Passive flow control around a semi-circular cylinder using porous coatings. Int J Flow Contr 6(1):43–60
Shi X-D, Feng L-H (2015) Control of flow around a circular cylinder by bleed near the separation points. Exp Fluids 56:214
Sirenko V, Pavlovsky R, Rohatgi US (2012) Methods of reducing vehicle aerodynamic drag. ASME 2012 Summer Heat Transfer Conf.
Williamson CHK, Govardhan R (2004) Vortex-induced vibrations. Annu Rev Fluid Mech 36:413–455
Wu Y, Christensen KT (2006) Population trends of spanwise vortices in wall turbulence. J Fluid Mech 568(1):55–76
Yajima Y, Sano O (1996) A note on the drag reduction of a circular cylinder due to double rows of holes. Fluid Dynam Res 18(4):237–243
Zhou J, Adrian RJ, Balachandar S, Kendall TM (1999) Mechanisms for generating coherent packets of hairpin vortices in channel flow. J Fluid Mech 387:353–396
Acknowledgements
This work was supported by the Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, as part of the start-up package of L. P. Chamorro. The authors thank the help of undergraduate students Dylan Harmon and Matthew Sadowski.
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Hamed, A.M., Vega, J., Liu, B. et al. Flow around a semicircular cylinder with passive flow control mechanisms. Exp Fluids 58, 22 (2017). https://doi.org/10.1007/s00348-017-2309-y
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DOI: https://doi.org/10.1007/s00348-017-2309-y