DOI QR코드

DOI QR Code

Control of the flow past a sphere in a turbulent boundary layer using O-ring

  • Okbaz, Abdulkerim (Dogus University, Engineering Faculty, Mechanical Engineering Department) ;
  • Ozgoren, Muammer (Necmettin Erbakan University, Faculty of Aviation and Space Sciences, Aeronautical Engineering Department) ;
  • Canpolat, Cetin (Cukurova University, Faculty of Engineering, Biomedical Engineering Department) ;
  • Sahin, Besir (Cukurova University Faculty of Engineering, Mechanical Engineering Department) ;
  • Akilli, Huseyin (Istanbul Aydin University, Engineering Faculty, Mechanical Engineering Department)
  • 투고 : 2021.02.02
  • 심사 : 2022.06.07
  • 발행 : 2022.07.25

초록

This research work presents an experimental study's outcomes to reveal the impact of an O-ring on the flow control over a sphere placed in a turbulent boundary layer. The investigation is performed quantitatively and qualitatively using particle image velocimetry (PIV) and dye visualization. The sphere model having a diamater of 42.5 mm is located in a turbulent boundary layer flow over a smooth plate for gap ratios of 0≤G/D≤1.5 at Reynolds number of 5 × 103. Flow characteristics, including patterns of instantaneous vorticity, streaklines, time-averaged streamlines, velocity vectors, velocity fluctuations, Reynolds stress correlations, and turbulence kinetic energy (), are compared and discussed for a naked sphere and spheres having O-rings. The boundary layer velocity gradient and proximity of the sphere to the flat plate profoundly influence the flow dynamics. At proximity ratios of G/D=0.1 and 0.25, a wall jet is formed between lower side of the sphere and flat plate, and velocity fluctuations increase in regions close to the wall. At G/D=0.25, the jet flow also induces local flow separations on the flat plate. At higher proximity ratios, the velocity gradient of the boundary layer causes asymmetries in the mean flow characteristics and turbulence values in the wake region. It is observed that the O-ring with various placement angles (𝜃) on the sphere has a considerable alteration in the flow structure and turbulence statistics on the wake. At lower placement angles, where the O-ring is closer to the forward stagnation point of the sphere, the flow control performance of the O-ring is limited; however, its impact on the flow separation becomes pronounced as it is moved away from the forward stagnation point. At G/D=1.50 for O-ring diameters of 4.7 (2 mm) and 7 (3 mm) percent of the sphere diameter, the -ring exhibits remarkable flow control at 𝜃=50° and 𝜃=55° before laminar flow separation occurrence on the sphere surface, respectively. This conclusion is yielded from narrowed wakes and reductions in turbulence statistics compared to the naked sphere model. The O-ring with a diameter of 3 mm and placement angle of 50° exhibits the most effective flow control. It decreases, in sequence, streamwise velocity fluctuations and length of wake recovery region by 45% and 40%, respectively, which can be evaluated as source of decrement in drag force.

키워드

참고문헌

  1. Achenbach, E. (1971), "Influence of surface roughness on the cross-flow around a circular cylinder", J. Fluid Mech., 46(2), 321-335. https://doi.org/10.1017/s0022112071000569.
  2. Achenbach, E. (1972), "Experiments on the flow past spheres at very high Reynolds numbers", J. Fluid Mech., 54(3), 565-575. https://doi.org/10.1017/S0022112072000874.
  3. Achenbach, E. (1974), "Vortex shedding from spheres", J. Fluid Mech., 62(2), 209-221. https://doi.org/10.1017/S0022112074000644.
  4. Canpolat, C. (2015), "Characteristics of flow past a circular cylinder with a rectangular groove", Flow Meas. Instrum, 45, 233-246. https://doi.org/10.1016/j.flowmeasinst.2015.06.028.
  5. Canpolat, C. and Sahin, B. (2017), "Influence of single rectangular groove on the flow past a circular cylinder", Int. J. Heat Fluid Flow, 64, 79-88. https://doi.org/10.1016/j.ijheatfluidflow.2017.02.001.
  6. Chae, S., Lee, S., Kim, J. and Lee, J.H. (2019), "Adaptive-passive control of flow over a sphere for drag reduction", Phys. Fluids, 31, 015107. https://doi.org/10.1063/1.5063908.
  7. Choi, H., Jeon, W.-P. and Kim, J. (2008) "Control of Flow Over a Bluff Body", Annu. Rev. Fluid Mech., 40, 113-139. https://doi.org/10.1146/annurev.fluid.39.050905.110149.
  8. Choi, J., Jeon, W.-P. and Choi, H. (2010). "Mechanism of drag reduction by dimples on a sphere", Phys. Fluids, 18(4), 041702. https://doi.org/10.1063/1.2191848.
  9. Chomaz, J.M., Bonneton, P. and Hopfinger, E.J. (1993), "The structure of the near wake of a sphere moving horizontally in a stratified fluid", J. Fluid Mech., 254, 1-21. https://doi.org/10.1017/S0022112093002009.
  10. Darekar, R.M. and Sherwin, S.J. (2001), "Flow past a squaresection cylinder with a wavy stagnation face" J. Fluid Mech. 426, 263-295. https://doi.org/10.1017/S0022112000002299.
  11. Derakhshandeh, J.F. and Mahbub Alam, Md., (2018), "Flow structures around rectangular cylinder in the vicinity of a Wall", Wind Struct. An Int. J., 26(5), 293-304. http://dx.doi.org/10.12989/was.2018.26.5.293.
  12. Derakhshandeh, J.F. and Mahbub Alam, M.D. (2020), "Reynolds number effect on the flow past two tandem cylinders", Wind Struct., 30(5), 475-483. http://dx.doi.org/10.12989/was.2020.30.5.475.
  13. Gozmen, B. and Akilli, H. (2014), "Flow control downstream of a circular cylinder by a permeable cylinder in deep water", Wind Struct. 19(4), 389-404. http://dx.doi.org/10.12989/was.2014.19.4.389.
  14. Hassanzadeh, R., Sahin, B. and Ozgoren, M. (2011), "Numerical investigation of flow structures around a sphere", Int. J. Comut. Fluid Dyn., 25, 535-545. https://doi.org/10.1080/10618562.2011.633489.
  15. Heng, H. and Sumner, D. (2020), "Wind loading of a finite prism: aspect ratio, incidence and boundary layer thickness effects", Wind Struct., 31(3), 255-267. http://dx.doi.org/10.12989/was.2020.31.3.255.
  16. Leblond, A. and Hardy, C. (2005), "Unifying calculation of vortex-induced vibrations of overhead conductors", Wind Struct. 8(2), 79-88. http://dx.doi.org/10.12989/was.2005.8.2.079.
  17. Lin, Y.F., Bai, H.L. and Alam, M.M. (2016), "The turbulent wake of a square prism with wavy faces", Wind Struct. 23(2), 127-142. https://doi.org/10.12989/was.2016.23.2.127.
  18. Li, K., Qian, G., Ge, Y., Zhao, L. and Di, J. (2019), "Control effect and mechanism investigation on the horizontal flow-isolating plate for PI shaped bridge decks\' VIV stability", Wind Struct. 28(2), 99-110. http://dx.doi.org/10.12989/was.2019.28.2.099.
  19. Li, Q., Cao, H., Li, G., Li, S. and Liu, D. (1999), "Optimal design of wind-induced vibration control of tall buildings and high rise structures", Wind Struct., 2(1), 69-83. http://dx.doi.org/10.12989/was.1999.2.1.069.
  20. Strommen, E. and Hjorth-Hansen, E. (2001), "On the use of tuned mass dampers to suppress vortex shedding induced vibrations", Wind Struct., 4(1), 19-30. http://dx.doi.org/10.12989/was.2001.4.1.019.
  21. Moradiana, N., Tingb, D.S.K. and Cheng, S. (2011), "Advancing drag crisis of a sphere via the manipulation of integral length scale", Wind Struct., 14(1), 35-53. https://doi.org/10.12989/was.2011.14.1.035.
  22. Norman, A.K. and McKeon, B.J. (2011), "The effect of a small isolated roughness element on the forces on a sphere in uniform flow", Exp. Fluids, 51, 1031-1045. https://doi.org/10.1007/s00348-011-1126-y
  23. Okbaz, A., Ozgoren, M., Dogan, S., Canpolat, C., Akilli, H. and Sahin, B. (2019), "Control of the flow past a sphere near a flat wall using passive jet", Ocean Eng. 187, 106120. https://doi.org/10.1016/j.oceaneng.2019.106120.
  24. Ozgoren, M. (2013), "Flow structures around an equilateral triangle arrangement of three spheres", Int. J. Multiph. Flow, 53, 54-64. https://doi.org/10.1016/j.ijmultiphaseflow.2013.02.001.
  25. Ozgoren, M., Okbaz, A., Dogan, S., Sahin, B. and Akilli, H. (2013), "Investigation of flow characteristics around a sphere placed in a boundary layer over a flat plate", Exp. Therm. Fluid Sci., 44, 62-74. https://doi.org/10.1016/j.expthermflusci.2012.05.014.
  26. Ozgoren, M., Okbaz, A., Dogan, S., Sahin, B. and Akilli, H. (2012), "Turbulent shear flow downstream of a sphere with and without an o-ring located over a plane boundary", EPJ Web Conf., 25, 01066. https://doi.org/10.1051/epjconf/20122501066.
  27. Ozgoren, M., Pinar, E., Sahin, B. and Akilli, H. (2011), "Comparison of flow structures in the downstream region of a cylinder and sphere", Int. J. Heat Fluid Flow, 32(6), 1138-1146. https://doi.org/10.1016/j.ijheatfluidflow.2011.08.003.
  28. Rastan, M.R., Sohankar, A., Doolan, C., Moreau, D., Shirani, E., and Alam, M.M. (2019), "Controlled flow over a finite square cylinder using suction and blowing", Int. J. Mech. Sci., 156, 410-434. https://doi.org/10.1016/j.ijmecsci.2019.04.013.
  29. Sooraj, P., Ramagya, M., Khan, M., Sharma, A. and Agrawal, A. (2020). "Effect of superhydrophobicity on the flow past a circular cylinder in various flow regimes", J. Fluid Mech., 897, A21. https://doi.org/10.1017/jfm.2020.371.
  30. Son, K., Choi, J., Jeon, W.P. and Choi, H. (2011), "Mechanism of drag reduction by a surface trip wire on a sphere", J. Fluid Mech. 672, 411-427. https://doi.org/10.1017/S0022112010006099.
  31. Terwagne, D., Brojan, M. and Reis, P.M. (2014), "Smart Morphable Surfaces for Aerodynamic Drag Control", Adv. Mater., 26, 6608-6611. https://doi.org/10.1002/adma.201401403.
  32. Tiwari, S.S., Pal, E., Bale, S., Minocha, N., Patwardhan, A.W., Nandakumar, K. and Joshi, J.B. (2020), "Flow past a single stationary sphere, 2. Regime mapping and effect of external disturbances", Powder Technol., 365, 215-243. https://doi.org/10.1016/j.powtec.2019.04.032.
  33. Tsuji, Y., Morikawa, Y. and Terashima, K. (1982), "Fluid-dynamic interaction between two spheres", Int. J. Multiph. Flow, 8(1), 71-82. https://doi.org/10.1016/0301-9322(82)90008-8.
  34. Tsutsui, T. (2008), "Flow around a sphere in a plane turbulent boundary layer", J. Wind Eng. Ind. Aerod., 96(6-7), 779-792. https://doi.org/10.1016/j.jweia.2007.06.031.
  35. Van Hout, R., Eisma, J., Elsinga, G.E. and Westerweel, J. (2018), "Experimental study of the flow in the wake of a stationary sphere immersed in a turbulent boundary layer", Phys. Rev. Fluids, 3(2), 024601. https://doi.org/10.1103/PhysRevFluids.3.024601.
  36. Wang, J. and Feng, L. (2018), Flow Control Techniques and Applications, Cambridge University Press. https://doi.org/10.1017/9781316676448.
  37. Zeng, L., Balachandar, S. and Fischer, P. (2005), "Wall-induced forces on a rigid sphere at finite Reynolds number", J. Fluid Mech., 536, 1-25. https://doi.org/10.1017/S0022112005004738.
  38. Zhang, J., Yang, Q. and Li, Q.S. (2013), "Developments and applications of a modified wall function for boundary layer flow simulations", Wind Struct., 17, 361-377. https://doi.org/10.12989/was.2013.17.4.361.
  39. Zhao, H., Liu, X., Li, D., Wei, A., Luo, K. and Fan, J. (2016), "Vortex dynamics of a sphere wake in proximity to a wall", Int. J. Multiph. Flow, 79, 88-106. https://doi.org/10.1016/j.ijmultiphaseflow.2015.10.005.