Figure 8.3 Flow past a circular cylinderas a function of Reynolds number between one and a million. From Richardson (1961). The appropriate flows are: A - a toothpick moving at 1mm/s; B - finger moving at 2cm/s; F - hand out a car window at 60mph. All flow at the same Reynolds number has the same streamlines. Flow past a 10cm diameter cylinder at 1cm/s looks the same as 10cm/s flow past a cylinder 1cm in diameter because inboth cases Re = 1000.