In this article, the effect of duct width on fully developed turbulent airflow characteristics in a corrugated duct is investigated numerically. The k-epsilon model is adopted for turbulent closure, and the governing equations in three dimensions are solved using a finite volume technique. The calculations were performed with the width aspect ratio (interwall spacing/channel width) ranging from 0.1 to 1.0, with the Reynolds numbers ranging from about 2000 to 15000, and corrugation angles of 30degrees and 45degrees. An experimental study was also performed for pressure drop, velocity, and flow visualization. The detailed predictions are compared with the experimental measurements, and a good agreement between the two is obtained.