CFD/CSD方法分析动力效应对民机气动特性影响

基于Reynolds average Navier-Stockes(RANS)的三维Navier-Stokes流场控制方程耦合结构静力学方程时域分析方法，研究了带有发动机的民用飞机其动力效应对全机气动性能的影响。首先采用数值方法对发动机进排气边界条件进行了模拟，分析了带动力的涡扇发动机模型的流场，并将计算结果与实验进行比较，验证边界条件处理的准确性；以此为基础，考虑结构弹性变形，采用计算流体动力学/计算结构动力学(CFD/CSD)耦合的方法，分别对通气和带动力的翼吊发动机全机的气动性能进行了研究。结果表明:基于通气构型预测的升阻力系数，气动载荷和压心位置与考虑动力效应后的计算结果存在明显不同。弹性变形又会加剧这一差异，使得全机的升阻比下降约12.6%，升力系数下降约8.9%,压心位置后移。数值算例显示，在靠近发动机区域气动载荷受动力效应影响显著，远离该区域，弹性变形效应占主要影响因素，因此在进行带动力效应的民机气动性能分析时，考虑弹性变形的影响是十分必要的。 

Analysis of civil aircraft aerodynamic characteristics with powered effects based on CFD/CSD method

Fluid structure coupling method based on three dimensional Reynolds average Navier-Stockes (RANS) equations and static equation was used for study on aerodynamic characteristics of the civil aircraft with powered effects.Firstly,numerical calculation was adopted to simulate the boundary condition of the fan-inlet and jet-exhaust and analyze the flow field of the turbine powered simulator.The numerical results agreed well with those from the wind tunnel experiment.Furthermore,the research on the performance of the aerodynamic characteristics of the aircraft with powered nacelle and with flow-through nacelle was conducted through computational fluid dynamics (CFD)/computational structure dynamics (CSD) approach.The numerical results indicate that the aerodynamic performances such as lift coefficient,drag coefficient,aerodynamic loads and pressure center location based on powered nacelles differ obviously from flow-through ones.Elastic effect can increase the differences so that it can make lift-drag ratio decrease by approximately 12.6％,lift coefficient decrease by 8.9 ％,and pressure center location move backwards.The numerical example showed that the aerodynamic loads close to the nacelles were influenced notably by powered effects while those far from the nacelles were affected mainly by the elastic effects.Consequently,it is necessary to consider the elastic effects when analyzing civil aircraft aerodynamic characteristics.