Journal of computational fluids engineering (한국전산유체공학회지)

Korean Society of Computational Fluids Engineering (한국전산유체공학회)
권호 표지
DOI QR코드

DOI QR Code

WALL EFFECTS ON LAMINAR FLOW OVER A CUBE

정육면체 주위 층류 유동에 근처 벽면이 미치는 영향

  • 김동주 (금오공과대학교 기계공학과)
  • Received : 2011.02.11
  • Accepted : 2011.03.18
  • Published : 2011.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

Laminar flow over a cube near a plane wall is numerically investigated in order to understand the effects of the cube-wall gap on the flow characteristics as well as the drag and lift coefficients. The main focus is placed on the three-dimensional vortical structures and its relation to the lift force applied on the cube. Numerical simulations are performed for the Reynolds numbers between 100 and 300, covering several different flow regimes. Without a wall nearby, the flow at Re=100 is planar symmetric with no vortical structure in the wake. However, when the wall is located close to the cube, a pair of streamwise vortices is induced behind the cube. At Re=250, the wall strengthens the existing streamwise vortices and elongates them in the streamwise direction. As a result, the lift coefficients at Re=100 and 250 increase as the cube-wall gap decreases. On the other hand, without a wall, vortex shedding takes place at Re=300 in the form of a hairpin vortex whose strength changes in time. The head of hairpin vortex or loop vortex, which is closely related to the lift force, seems to disappear due to the nearby wall. Therefore, unlike at Re=100 and 250, the lift coefficient tends to decrease more or less as the cube approaches the wall.

Keywords

References

  1. 1990, Strykowski, P.J. and Sreenivasan, K.R., "On the formation and suppression of vortex shedding at low Reynolds numbers," J. Fluid Mech., Vol.218, pp.71-107. https://doi.org/10.1017/S0022112090000933
  2. 1996, Williamson, C.H.K., "Vortex dynamics in the cylinder wake," Annu. Rev. Fluid Mech., Vol.28, pp.477-539. https://doi.org/10.1146/annurev.fl.28.010196.002401
  3. 1996, Kwon, K. and Choi, H., "Control of laminar vortex shedding behind a circular cylinder using splitter plates," Phys. Fluids, Vol.8, pp.479-486. https://doi.org/10.1063/1.868801
  4. 1990, Sakamoto, H. and Haniu, H., "A study on vortex shedding from spheres in a uniform flow," J. Fluids Eng., Vol.112, pp.386-392. https://doi.org/10.1115/1.2909415
  5. 1999, Johnson, T.A. and Patel, V.C., "Flow past a sphere up to a Reynolds number of 300," J. Fluid Mech., Vol.378, pp.19-70. https://doi.org/10.1017/S0022112098003206
  6. 1999, Mittal, R., "Planar symmetry in the unsteady wake of a sphere," AIAA J., Vol.37, No.3, pp.388-390. https://doi.org/10.2514/2.722
  7. 2002, Kim, D. and Choi, H., "Laminar flow past a sphere rotating in the streamwise direction," J. Fluid Mech., Vol.461, pp.365-386.
  8. 2006, Yun, G., Kim, D. and Choi, H., "Vortical structures behind a sphere at subcritical Reynolds numbers," Phys. Fluids, Vol.18, pp.015102-1-14. https://doi.org/10.1063/1.2166454
  9. 2008, 김동주, "구 주위의 비정상 면대칭 및 비대칭 유동의 특성," 한국전산유체공학회지, 제13권 제4호, pp.39-44.
  10. 1990, Raul, R., Bernard, P.S. and Buckley, Jr., F.T., "An application of the vorticity-vector potential method to laminar cube flow," Int. J. Numer. Methods Fluids, Vol.10, pp.875-888. https://doi.org/10.1002/fld.1650100803
  11. 1991, Raul, R. and Bernard, P.S., "A numerical investigation of the turbulent flow field generated by a stationary cube," J. Fluids Eng., Vol.13, pp.216-222.
  12. 2004, Saha, A.K., "Three-dimensional numerical simulation of the transition of flow past a cube," Phys. Fluids, Vol.16, pp.1630-1646. https://doi.org/10.1063/1.1688324
  13. 2008, 김동주, "직육면체를 지나는 층류 유동," 한국전산유체공학회지, 제13권 제1호, pp.57-62.
  14. 1978, Bearman, P.W. and Zdravkovich, M.M., "Flow around a circular cylinder near a plane boundary," J. Fluid Mech., Vol.89, pp.33-47. https://doi.org/10.1017/S002211207800244X
  15. 1998, Kim, M.S. and Geropp, D., "Experimental investigation of the ground effect on the flow around some two-dimensional bluff bodies with moving-belt technique," J. Wind Eng. Ind. Aerodyn., Vol.74-76, pp.511-519. https://doi.org/10.1016/S0167-6105(98)00046-4
  16. 2008, Nishino, T., Roberts, G.T. and Zhang, X., "Unsteady RANS and detached-eddy simulations of flow around a circular cylinder in ground effect," J. Fluids Struct., Vol.24, pp.18-33. https://doi.org/10.1016/j.jfluidstructs.2007.06.002
  17. 2005, Zeng, L., Balachandar, S. and Fischer, P., "Wall-induced forces on a rigid sphere at finite Reynolds number," J. Fluid Mech., Vol.536, pp.1-25. https://doi.org/10.1017/S0022112005004738
  18. 2001, Kim, J., Kim, D. and Choi, H., "An immersed boundary finite-volume method for simulations of flow in complex geometries," J. Comput. Phys., Vol.171, pp.132-150. https://doi.org/10.1006/jcph.2001.6778
  19. 1995, Jeong, J. and Hussain, F., "On the identification of a vortex," J. Fluid Mech., Vol.285, pp.69-94. https://doi.org/10.1017/S0022112095000462