Contributed by the Fluids Engineering Division for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received by the Fluids Engineering Division January 13, 2004; revised manuscript received August 12, 2004. Review conducted by: H. Johari.
In the design of contractions for low-speed wind tunnels, several desirable characteristics of the wall profile are identified, primarily consisting of a wall profile described by a function having zero first- and second-order derivatives, and the radii of curvature at the inlet and outlet roughly proportional to the area 1. This condition would be the most favorable to achieve flow uniformity, thin boundary layers, and negligible losses 2. A contraction profile, described by a fifth degree polynomial, has been developed by Bell and Mehta 3 and has been repeatedly employed successfully in contraction design in two and three dimensions. This polynomial has proven so successful that it has largely become the design...
