Figure 1
Experimental apparatus: Water is pumped by way of a settling chamber into a 26-m long
straight pipe that has a diameter of D = 4 cm. The settling chamber as well as the inlet shape were
designed to minimize disturbances from the inlet. The entire pipe is thermally insulated to
avoid heat convection, which would distort the flow profile. The fully developed laminar flow is
perturbed 350D from the inlet, and particle image velocimetry measurements are performed
another 150D downstream (image and text: B Hof et al. 2004 Science 305 1594)