Effect of Reynolds number on upper cowl flow separation

Abstract

This paper describes testing on subsonic inlet cowlings for high-bypass-ratio turbofan engines, conducted in a low-speed pressurized wind tunnel. These new data bridge the gap between earlier low Reynolds number model data for cowl flow separation and full-scale flight conditions. Innovative model test approaches were employed and are described. New cowl flow separation data matched previously obtained data at comparable Reynolds numbers. Higher Reynolds number data, up to flight value levels, behaved in an orderly fashion and were suitable for improving currently available theroretical descriptions of the phenomena governing engine inoperative cowl flow separation.