The flow around a circular cylinder is a simple flow and has been studied for a long time. However, like Isaac Newton describing the motion of a falling apple, it is often by gaining a deeper understanding of simple phenomena that we learn useful lessons for wider contexts.
This video shows some of the results of numerical simulations that modelled laminar flow around a circular cylinder. The separation of the flow and the formation of the wake were controlled by suction through the cylinder surface. The suction profiles were optimised at a variety of Reynolds Numbers to determine how the separation can most effectively be prevented. The optimised profiles - in particular the centre of suction and strength, were found to be dependent on the Reynolds number (or alternatively, on the original separation angle) with a predictable trend.