Physiological Flow Studies Unit (PFSU) The Physiological Flow Studies Unit was established at Imperial College London in 1966 within the Department of Aeronautics. The Unit's work covered the areas of arterial and respiratory fluid mechanics. C.G. Caro, a physiologist at St Thomas's Hospital Medical School, London first approached Lighthill in November 1964 about collaboration with a mathematician or fluid dynamicist. He became Director of the Physiological Flow Studies Unit. 1964-1967