On the Characteristics of Anti-contamination Devices on Attachment-Line of Subsonic Transport Aircraft

Abstract

AbstractThe natural laminar flow (NLF) wing design approach effectively reduces the fuel consumption and environmental impact by reducing the friction drag for a subsonic civil transport aircraft. This study conducts a numerical analysis based on the Reynolds-averaged Navier–Stokes equations applied to a technology reference aircraft, TRA2022 (120 pax) developed by Japan Aerospace Exploration Agency (JAXA), to analyze the characteristics of a passive flow control device known as the anti-contamination device (ACD), on an attachment line. It is introduced to prevent the propagation of contaminated flow from the fuselage to the wing. Three different types of ACDs are considered: split ACD, chevron ACD, and streamwise groove. The split ACD can provide a wider area to apply the NLF design because it is placed at the wing-body junction. However, it significantly affects the aerodynamic characteristics. Conversely, the chevron ACD and streamwise groove do not significantly affect the characteristics. The split and chevron ACD do not cause flow separation or additional disturbance to isolate the contaminated flow. The streamwise groove includes a turbulent vortex along the groove along with the mechanism used to prevent the contamination flow, which corresponds to this vortex. The effect of the angle of attack between the end and beginning of the cruise flight is analyzed. The change in the boundary layer thickness immediately upstream of the apex of the chevron ACD is approximately 14% of the ACD height, and it can be increased locally based on the ACD shape. The span of the split ACD and the height of the chevron ACD must be considered this effect to ensure their decontamination characteristics.KeywordsNatural laminar flowLaminar flow controlAttachment-line transitionAerodynamic device