Design Optimization of Lambda-Wing Planform and Vortex Generators for Longitudinal Instability Alleviation

IF 1.5 3区工程技术 Q2 ENGINEERING, AEROSPACE

Journal of Aircraft Pub Date : 2023-11-02 DOI:10.2514/1.c037495

Seonguk Lee, Chongam Kim

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Abstract

This paper focuses on optimizing the planform and vortex generators (VGs) to improve longitudinal stability of the lambda-wing aircraft by alleviating pitchup. The optimizations are performed in two stages using a Reynolds-averaged Navier–Stokes (RANS) solver that can accurately capture the vortical flow structure, affecting the pitchup. First, the planform configuration is optimized to minimize the rise in the pitching moment while maintaining aerodynamic and stealth performances. The designed planform delays the pitchup by 4 deg and increases the usable lift by 31% due to the leading-edge vortex (LEV) flow over the outboard wing. Second, the VGs are installed and optimized to reduce the sudden increase in the pitching moment at high angles of attack. The designed VGs partially eliminate the separated flow and recover the LEV on the outboard wing, suppressing the radical change in the pitching moment by 75%. Some quantitative difference in aerodynamic coefficients is observed in unsteady RANS computations, but the vortical flow unsteadiness minimally affects the flow structure, and the stability improvement remains over 80%. Overall, the generation and sustainability of the LEV are critical aerodynamic factors to secure longitudinal stability in designing the lambda-wing aircraft.

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用于缓解纵向失稳的λ翼平台和涡发生器设计优化

本文主要研究如何通过对平台和涡发生器的优化设计，以减轻俯仰现象，提高小翼飞机的纵向稳定性。优化分两个阶段进行，使用reynolds -average Navier-Stokes (RANS)求解器，该求解器可以准确捕获影响俯仰的涡流结构。首先，平台结构进行了优化，以尽量减少俯仰力矩的上升，同时保持气动和隐身性能。由于前缘涡(LEV)的作用，设计的平台将俯仰延迟了4度，并将可用升力提高了31%。其次，安装并优化了俯仰力矩，减小了大迎角下俯仰力矩的突然增大。设计的VGs部分消除了分离流并恢复了外翼的LEV，将俯仰力矩的剧烈变化抑制了75%。在非定常RANS计算中，气动系数有一定的定量差异，但旋涡非定常对流动结构的影响最小，稳定性提高保持在80%以上。总的来说，LEV的产生和可持续性是保证兰博翼飞机纵向稳定性的关键气动因素。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Aircraft 工程技术-工程：宇航

CiteScore

4.50

自引率

31.80%

发文量

141

审稿时长

6 months

期刊介绍： This Journal is devoted to the advancement of the applied science and technology of airborne flight through the dissemination of original archival papers describing significant advances in aircraft, the operation of aircraft, and applications of aircraft technology to other fields. The Journal publishes qualified papers on aircraft systems, air transportation, air traffic management, and multidisciplinary design optimization of aircraft, flight mechanics, flight and ground testing, applied computational fluid dynamics, flight safety, weather and noise hazards, human factors, airport design, airline operations, application of computers to aircraft including artificial intelligence/expert systems, production methods, engineering economic analyses, affordability, reliability, maintainability, and logistics support, integration of propulsion and control systems into aircraft design and operations, aircraft aerodynamics (including unsteady aerodynamics), structural design/dynamics , aeroelasticity, and aeroacoustics. It publishes papers on general aviation, military and civilian aircraft, UAV, STOL and V/STOL, subsonic, supersonic, transonic, and hypersonic aircraft. Papers are sought which comprehensively survey results of recent technical work with emphasis on aircraft technology application.