這是97成大水利的題目@@ Hele-Shaw flow is the viscous flow between two infinite, parallel plates of small gap under low Reynolds number. In laboratory, we often use dye to observe the streamlines of the potential flows around some smooth or blunt bodies, or the potential flow disturbed by sources or sinks. Please describe (a) why those smoke line can be recognized as the streamlines. (b) why the viscous flow pattern can be considered as the similarity of two-dimensional potential flow. (c) why, however, you may still observe some particular phenomena like flow separations or wakes, which are obviously not the phenomena of potential flows. 另外想再問一題也是97成大水利的 因為 題目有圖不太好畫 所以我把題目跟圖 放到上傳圖片的網站上 http://yfrog.com/3u32197j 這是imageshack的空間 不過題目我一樣打出來好了 A closed, fully-filled, circular water tank, of radius one meter and height 3 meter, rotates at a constant speed of 30 rpm's about the generator, as shown in the figure. Three points A, B, C, located horizontally on the bottom of tank at distances 0.0, 0.5, and 1.0 neters, respectively, from the centerline have the measured pressure as Pa, Pb, and Pc (a) Please write down the pressure-difference ratio of r=(Pb-Pa)/(Pc-Pa); (b) If we move these points from the bottom surface to the top cover, what does r become? (c) What is the force increment on the tank wall due to the increasing rotation of tank bu twice? (Using water density=1000 kg/m^3 , g=10m/s^2 in your calculation for simplicity) 我想問上面這題 他是個封閉的圓筒 而且裡面的水是完整填充的 這樣的題目 還可以使用 dp=ρr(w^2)dr-ρgdz 這個公式嗎 --

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