二次元矩形粗面境界層の粗さ要素近傍における運動量交換機構 : 溝内部渦の可視化観察(流体工学,流体機械)

概要

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Flow visualization has been performed in the vicinity of a roughness element for the rough wall boundary layers developing over the roughness with pitch ratio p of 2 and 4 at a low Reynolds-number. The momentum thickness Reynolds numbers at streamwise distance x=865mm for p=2 and 4 were 300 and 500, respectively. For p=2, typical flow patterns are classified into 4 patterns which are consistent with those of Townes et al., otherwise 3 patterns were recognized for p=4. The frequency f_m, the sum of the frequency of each flow pattern, which is closely associated with the momentum exchange normalized with the cavity width b and the friction velocity u_τ for p=4 takes larger value compared with that of p=2. This quantitative result can be related that the pressure drag acting on a roughness element for p=4 is larger than that of p=2.
一般社団法人日本機械学会の論文
2005-10-25