The hydraulic test tunnel at the service of aerospace research

For over twenty years ONERA has operated at its Chatillon Center near Paris, a hydraulic test tunnel devoted to the visualization of flows at low speed. This long period of uninterrupted service made it possible to extend widely the possibilities and performance of the installations and their equipment, improve test methods, and take up a large variety of studies concerning both fundamental research and applications in the aerospace or industrial field. An up to date description of this experimental technique is presented and a survey of the most notable results given.