Albert Alan Townsend FRS[1] (22 Jan 1917 – 31 Aug 2010) was an Australian scientist specialized in fluid dynamics.

He was the author of the textbook The Structure of Turbulent Shear Flow (1956; 1976; Cambridge University Press).

During the Second World War, he joined military research and worked on aerodynamics in Australia.

In this period, he met George Batchelor and started to research in fluid dynamics.

He obtained PhD in 1947 and the thesis title was Beta Ray Spectra of Light Elements and Turbulent Flow.