These course-notes are a draft and were prepared for a course in fall 2000 at ASU. ... For a very naive preview consider again the two examples given above. .... Definition 1.2.1 A vector field is a function that assigns to every point in (some subset of the) ..... Figure 1.3: Fluid flow around a cylinder and in a rocket exhaust.
https://math.la.asu.edu/~kawski/classes/mat362/handouts_slides/00notes.pdf