A wall-modelled large eddy simulation approach based on large scale parallel computing for post stall flow over an iced airfoil

基于大规模并行计算的结冰翼型失速流场特性数值模拟研究

¹ School of Computer Science, Northwestern Polytechnical University, Xi'an 710072, China
² Forecast Research Division, AVIC Xi'an Aeronautics Computing Technique Research Institute, Xi'an 710068, China

Received: 28 November 2022

Abstract

Safety evaluation for ice accretion is one of the most important jobs for the airworthiness certification of commercial aircraft. Ice accretion would induce strong performance degradation of lifting surfaces by modifying the geometry of the leading edge and the state of boundary layers, and inducing premature flow separation. In this paper, a wall-modelled large eddy simulation (WMLES) approach combined with high performance computing is presented and evaluated for numerical simulation of post stall flow at Mach number 0.12 and Reynolds number 3.5 million over an iced airfoil with angle of attack 6 degrees for business jet, which is known as the GL305/944 airfoil with horn ice. Both RANS and an improved DDES (IDDES) based on SST model are also completed to validate the results. The results are compared with the experimental data in details that includes total forces, velocity profile, averaged velocity field, RMS of pulsating velocity, et al. It is concluded that the WMLES approach presented here can greatly improve the numerical accuracy for post stall flow with large separation; Basically, WMLES can relatively accurately predict the total forces, the pressure rooftop length and the pressure recovery, and the shear layer instability induced by the horn ice.The relative error of lift coefficient for WMLES is only 0.47%, which is far less than RANS with -26.7%.

摘要

结冰安全性评估是民用飞机适航的重要工作内容。翼面结冰将引起机翼前缘外形及边界层状态变化，并诱导大范围分离，进而导致飞行器升力面性能急剧降低，甚至带来严重的飞行安全问题。针对常规方法难以有效准确预测结冰翼型后失速流场空气动力学特性的问题，发展了一种结合大规模并行计算和壁面模化大涡模拟(WMLES)的有效数值计算方法，成功用于双角冰结冰翼型GL305/944的后失速流场特性的数值模拟研究，取得了满意效果。数值模拟研究中，计算状态选取马赫数0.12，雷诺数3.5×10⁶，攻角6°，对应了该翼型在风洞试验中后失速附近的流动状态。作为对比，同时给出雷诺平均Navier-Stokes(RANS)方法及改进的时间延迟脱体涡模拟(IDDES)方法的计算结果，并与试验结果进行了综合比较。结果表明，WMLES是一种适于计算大范围分离流动的有效方法，针对结冰翼型后失速流场的数值预测，可大幅提高预测精度；针对文中的GL305/944结冰翼型，WMLES能相对准确地预测总体气动力、压力平顶长度和压力恢复，以及角状冰引起的剪切层失稳，且预测的升力系数相对误差仅为0.47%，远小于RANS方法的-26.7%。