@wikipediaFamily of curves that are instantaneously tangent to the velocity vector of the flow, showing direction in which a massless fluid element is travelling at any point in time
The loci of points of all the fluid particles that have passed continuously through a particular spatial point in the past. Dye steadily injected into the fluid at a fixed point extends along a streakline.
Fig. 1. Streaklines | Fig. 2. Streamlines (dash grey), pathline (solid red) and streakline (solid blue) |
...