Design of wind tunnel contractions with a rectangular cross section.

Abstract

In reviewing the available design methods of wind tunnel contractions with a rectangular cross section, the flow characteristics in these ducts have macroscopically been estimated by referring to the analytical results obtained for axisymmetrical or two dimensional contractions. However, the final design relies mostly on the sense and experience of the designer, and the design process is more an art than science. The present paper proposes how to evaluate such flow characteristics objectively, and shows that a contraction with no separation along the duct wall, with sufficient uniformity of exit flow and short axial length, can substantially be obtained by adjusting only two parameters which assign the velocity distribution at the center axis.