我們的實驗為探討圓柱體在二維垂直流動肥皂膜上的動力學行為。圓柱體設計為在肥皂膜上有旋轉的自由度。我們觀察到圓柱體在肥皂膜上有穩定(Steady)、擺動(Fluttering)、旋轉(Rotating)三種運動模式,還有兩個過渡時期的運動模式 - 擺動旋轉混合(Fluttering-Rotating mix)和停滯(Dull)。主要研究方向為在不同的肥皂膜和圓柱體的物理條件下,圓柱體運動行為變化的探討。我們發現了一個沒有單位的參數(P)用以描述圓柱體運動的轉變,而且圓柱體在肥皂膜上的運動跟其轉動慣量是無關的。 We present an experimental characterization of dynamics of a cylindrical rod in a vertically flowing soap film. The rod is setup to be capable of rotating freely in the soap film. The Steady(S), Fluttering(F), and Rotating(R) motions of the rods are observed, and there are two kinds of transitional motions –Fluttering-Rotating(FR) mix, and Dull(D). The dynamics of the flow field in the soap film and the transitions between different rod motions have been studied under different physical parameters of the rod and soap film. We find out a dimensionless parameter(P) to describe the transitions of the rod’s motions, which in the vertically flowing soap films have no concern with the moment of inertia.