Interference mechanism of engine exhaust on civil aircraft drag performance

Engine exhaust can lead to an interference effect on the aerodynamic performance, which is an important part of civil aircraft drag prediction. Powered engine simulation technique has already been introduced for wind-tunnel tests but has a high operating cost and may not provide much insight for the interference mechanism. The main purpose of this paper is to investigate the interference effect of engine exhaust on civil aircraft drag performance and its mechanism at low speed. The investigation is finished by computational fluid dynamics method and shows that 1) the interference effect on drag performance under different internal/external-bypass flow rates is revealed and 2) the interference mechanism is obtained by analyzing the velocity magnitude contours of local flowfields and pressure distributions of certain components that mainly contribute to the change of drag performance.