Simulation methodologies of engine noise shielding by wings within conceptual aircraft design

Abstract

The pursuit of greener aviation led to the investigation of new aircraft concepts. Disruptive aircraft configurations show great potential in reducing the ground noise impact, but extensive research is required before they can be manufactured. Tube-and-wing aircraft with over-the-wing engines, benefiting from noise shielding, are a more feasible option for midterm noise reduction targets. This work explores a low-noise version of the B747-400 considering over-the-wing engines, and a multidisciplinary procedure is used to calculate the aircraft and engine performance, the flight procedure, and the noise impact. Engine positions are found providing maximumengine noise shielding, reflected in a decrease in the sound exposure level (SEL) contours. These contours are calculated considering the wing leading edge as both a sharp and a curved edge. This work investigates whether a sharp leading-edge approximation is acceptable for first estimates of the optimal engines position and corresponding noise reduction values. From the results it is found that the maximumdecrease in theSEL obtained for the modified aircraft is 2 dB considering a sharp leading edge and 1.5 dB for a curved leading edge, for departure. For approach, the SEL contours do not show significant differences for the sharp and curved leading edge, with maximum noise reduction values of 3.5 dB for both cases.