A Small Wind Tunnel Significantly Improved by a Multi-Purpose, Two-Flexible-Wall Test Section

Abstract

A small open-return wind tunnel has been renovated to include a longer test section with a flexible roof and floor and improved entrance flow quality. The flexible-wall test section allows models with up to 30 percent nominal blockage to be tested, resulting in a significant increase in the maximum attainable Reynolds numbers. Interchangeable rigid side-wall panels allow flexibility of application which is essential for a university wind tunnel facility. Configurations have been developed for automotive, aerodynamic and atmospheric-boundary-layer testing. Data acquisition and wall positioning are at an economical semi-automated level of operation. The flexible-wall concept has been well-documented previously, and provides interference-free data without flow pattern assumptions after a few iterations of the roof and floor shape. Representative data are presented for a circular cylinder and an airfoil.