TRANSONIC AERODYNAMIC EFFICIENCY ASSESSMENT OF AN OPTIMISED SUPERSONIC CIVIL TRANSPORT USING CFD

This paper describes the effort undertaken at NLR to predict the aerodynamic efficiency of a supersonic civil transport aircraft design at transonic cruise. The aircraft design consists of a wing-fuselage combination, employing leading edge deflections and one deflected trailing edge flap to meet the transonic targets. A fuselage extension to mimic the wind tunnel model sting support is taken into account. The aerodynamic efficiency is predicted using a multi-block structured Navier-Stokes flow analysis system. The accuracy of the computed aerodynamic coefficients is investigated in a grid refinement study. Validation of the flow solutions is based on comparison with experimental data, available from the high-speed wind tunnel DNW-HST at NLR. Aerodynamic efficiency data at flight Reynolds number are obtained by CFD, using solution adaptive wall-normal grid spacing to adjust the boundary layer resolution. Also, the effect of the wind tunnel model sting support is investigated by additional computations on a similar configuration using the original upswept fuselage. It is shown that with present day CFD- capabilities one can predict aerodynamic efficiency for attached transonic flow around a supersonic civil transport design including deflected leading and trailing edge devices. Sufficient attention, however, has to be attributed to the quality of the computational grids.