National Taiwan University Dept Chem EngnHsu, Jyh-PingJyh-PingHsuHsieh, Yu-HengYu-HengHsieh2006-11-142018-06-282006-11-142018-06-282002http://ntur.lib.ntu.edu.tw//handle/246246/2006111501232995The behavior of a oc in a ow !eld is analyzed theoretically; in particular, the force it experienced is estimated. Here, a oc is simulated by an entity having a two-layer type of structure, and its porous nature mimicked by varying the relative magnitudes of the permeability of its inner layer and that of its outer layer. The results of numerical simulation reveal that, for the same volume-averaged permeability, the drag coe6cient of a oc with a heterogeneous structure is always much larger than that of a oc with a homogeneous structure. This is true regardless of the relative magnitudes of the permeability of the inner layer and that of the outer layer. The drag coe6cient of a oc is mainly determined by the part having a less porous structure. We show that for the same volume-averaged permeability, the more heterogeneous the structure of a oc is, the easier for the relation between the drag coe6cient and the Reynolds number to deviate from a Stokes’ law-like correlation.application/pdf205381 bytesapplication/pdfen-USflocporous structuredrag coefficienttwo-layer modeljournal article10.1016/S0009-2509(02)00170-7http://ntur.lib.ntu.edu.tw/bitstream/246246/2006111501232995/1/8357.pdf