Resistance To Motion In Fluids

(A) - (C) Reynolds's sketches of flow observation:    (A) Low speed (Low ReD)  (B) Higher speed (Higher ReD) (C) Spark illumination

(D) Reynolds's experimental apparatus

(Boundary Layer Analysis Figure 6-1 85,p 177)

The classic pipe flow experiments of Reynolds (1883).

Visualization of vortex shedding behind a circular cylinder (From Corning)