流体流动时某质元在空间所描绘的曲线称为它的流迹。它是同一流体质元运动规律的几何表示。与质点力学中质点的轨迹的含义是相同的，因此流迹上各点沿时间增加方向的切线表示改质元各时刻运动的方向。
一张好的星流迹相片，往往需要一个好的背景衬托，这相片以湖的倒影作背景就是一个十分好的选择。
Usually, a good background is needed for a good star trail photo, in this picture, the stars are reflected through a lake, which is a very nice shot.
沃尔特·卢因通过APOD向广大天体摄影师发起挑战——拍摄一幅360度星流迹的单曝光晴朗夜空照片。
Walter Lewin, though, has asked APOD to pose this as a challenge to astrophotographers: create a real single-exposure image of a clear night sky that features 360 degree star trails.
在PIV流迹显示试验中观察到在模型上下两侧发生流动分离，后方有两个大旋涡，且在两个旋涡中间回流处测点的风压系数大于附近测点。
In the PIV flow visualization experiment, flow separation takes place at the top and bottom edges and two large vortices behind the model that remain attached to the back of the model are observed.
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