{'fraction_non_alphanumeric': 0.03229527104959631, 'fraction_numerical': 0.015570934256055362, 'mean_word_length': 5.3321167883211675, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Aerodynamic Optimization of a Transonic Strut-Braced-Wing Regional Aircraft Based on the Reynolds-Averaged Navier-Stokes Equations

The aerodynamic design and fuel burn performance of a Mach 0.78 strut-braced-wing regional jet is investigated through aerodynamic shape optimization based on the Reynoldsaveraged Navier-Stokes equations. Conceptual-level multidisciplinary design optimization is first performed to size the strut-braced-wing aircraft for a design mission similar to the Embraer E190-E2, with a design range of 3,100 nmi at a maximum capacity of 104 passengers, and a maximum payload of 30,200 lb. For direct performance comparisons, a conventional tube-and-wing regional jet is also sized and optimized based on the same reference aircraft. Gradient-based aerodynamic shape optimization is then performed on wing-body-tail models of each aircraft, with the objective of drag minimization at cruise over a 500 nmi nominal mission. Design variables include twist and section shape degrees of freedom, which are realized through a free-form and axial deformation geometry control system, while nonlinear constraints include constant lift, zero pitching moment, minimum wing volume, and minimum maximum thickness-to-chord ratios. Results indicate that the optimizer is capable of mitigating shock formation, boundary-layer separation, and other flow interference effects from each wing design, including those within the wing-strut junction of the strut-braced wing. With current technology levels, the strut-braced-wing regional jet offers a 15.6% improvement in cruise lift-to-drag ratio over the equivalent conventional tube-and-wing aircraft, which translates to a 6.5% reduction in block fuel for the nominal mission.