Numerical Simulation of Flows Past Two Near-by Spheres

초록

A parametric study on the interactions of two near-by spheres in a uniform freestream is carried out using an immersed boundary method. The line connecting the centers of the two spheres are either aligned or inclined with respect to the direction of the freestream. The numerical results for single sphere and those for two near-by spheres aligned in the streamwise direction for the range of Re<220 are in good agreement with other authors' experimental and numerical results currently available.[Kim et al., 2001, J. Comput. Phys., 171, pp.132-150, Zhu et al., 1994, Int. J. Multiphase Flow, 20, pp.117-129.] Then, our investigation is mainly focused on the influence of the downstream sphere on the wake structure of the upstream sphere at Re=300 where the vortex shedding from single sphere is supposed to be unsteady planar symmetric. It turns out that significant changes in shedding characteristics are noticed depending on how close the two spheres are. In this talk, not only quantitative changes in the key physical parameters such as the force coefficients and shedding frequencies, but also qualitative changes in shedding patterns are reported and analyzed. This work was supported by grant No. R01-2002-000-00060-0 from the Basic Research Program of the Korea Science and Engineering Foundation.