摘要
新一代客机具有较高的巡航速度,跨声速抖振和雷诺数效应研究是其气动设计中的关键一环。采用基于k-ωSST湍流模型耦合延迟脱体涡模拟技术的高精度数值模拟方法,针对CHN-T2宽体客机气动标模开展了相关研究,并基于非定常计算明确了CHN-T2标模在巡航马赫数Ma=0.85、飞行雷诺数Re=5×10^(7)工况下的抖振始发迎角约为4.4°。结果表明,CHN-T2标模机翼在抖振超临界迎角下同时存在由激波弦向振荡主导的低频成分(St=0.0297)和由翼根尾缘复杂高压区主导的高频成分(St=0.314)。在雷诺数效应方面,从风洞实验雷诺数(Re=5×10^(6))到飞行雷诺数(Re=5×10^(7))巡航状态下,CHN-T2机翼激波位置后移约10%当地弦长,附面层高度降低1/2~1/10,进而引发升/阻力系数发生明显变化。升力系数和摩阻系数的雷诺数效应不随迎角改变,而压阻系数的雷诺数效应与迎角线性相关。同时,雷诺数变化会显著影响抖振非定常流场求解,过低的模拟雷诺数会导致激波振荡消失。
The next-generation passenger aircraft feature higher cruise speeds,rendering transonic buffet and Reynolds number effects pivotal in their aerodynamic design.This paper employs the high-precision delayed detached eddy simulation,based on the k-ωSST turbulence model,to investigate the aerodynamic characteristics of the CHN-T2 model for wide-body aircraft.Unsteady simulations demonstrate that,for a cruise Mach number of 0.85 and a Reynolds number of Re=5×10^(7),the critical angle of attack at which the transonic buffet manifests is 4.4°.Large-scale separation around the wing root trailing edge serves as an indicator for the presence of the transonic buffet of CHN-T2,which exhibits the low-frequency(St=0.0297)shock oscillation and highfrequency(St=0.314)fluctuations in the high-pressure region near the trailing edge of the wing root.Regarding the Reynolds number effects,as the Reynolds number increases from Re=5×10^(6) to 5×10^(7),the shock wave position on the CHN-T2 wing shifts aft by approximately 10%of the local chord length,and the boundary layer thickness decreases by 10% to 50%,resulting in considerable variation in the aerodynamic coefficients.It is further revealed that the Reynolds number effect on the lift and friction drag coefficients remains unchanged regardless of the angle of attack,whereas that on the pressure drag coefficient is linearly correlated with the angle of attack.Concurrently,the variation in the Reynolds number significantly affects the unsteady flow field of transonic buffet,with excessively low Reynolds numbers potentially leading to the disappearance of shock wave oscillations.An increase in the Reynolds number will significantly enhance the shock oscillation intensity but barely affect the high-frequency fluctuations at the wing root trailing edge.
作者
豆子皓
吴军强
高传强
张伟伟
DOU Zihao;WU Junqiang;GAO Chuanqiang;ZHANG Weiwei(School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,China;China Aerodynamics Research and Development Center,Mianyang 621000,China)
出处
《空气动力学学报》
CSCD
北大核心
2024年第8期93-107,I0002,共16页
Acta Aerodynamica Sinica
