The specifications for the design of an annular wind tunnel to study swirling flows is presented. The wind tunnel design is such that a researcher can control the following variables at entrance to the working section: the flow Reynolds and Mach numbers, the flow swirl angle, and the annulus geometry. Air is blown through the working section by a two stage axial flow compressor supplying 12 lbm./sec. with a pressure rise of 20 in. of water. Aspects of the mechanical and aerodynamic design are discussed in detail.