中文摘要：

在直升机非线性全量飞行动力学模型的基础上,提出了一种耦合计算流体力学（CFD）方法的前飞状态配平计算分析方法.为提高传统飞行动力学建模中的直升机旋翼、机身和尾桨等部件的气动力计算精度,降低对试验数据的依赖性,建立了一个以Navier-Stokes方程为控制方程且包含旋翼和尾桨动量源项的直升机气动干扰流场及气动力的计算方法.采用非结构网格技术生成围绕直升机的网格,空间方向采用Jameson中心差分格式进行离散,时间推进采用五步龙格库塔法,并添加人工黏性以抑制解的数值振荡等,同时采用当地时间步长、变系数的隐式残值光顺等方法加速流场收敛.在耦合CFD方法的配平计算中,建立了一种将CFD计算得到的气动力与飞行动力学中的气动力高效耦合的策略.在飞行动力学模型和CFD方法验证的基础上,以UH 60A直升机为研究对象,进行了耦合CFD方法的全机配平分析,最后检验了耦合CFD模型的直升机配平方法的收敛性和精度.结果表明,该方法可以有效地提高配平分析精度,满足工程分析要求.

英文摘要：

Based on the nonlinear numerical model of flight dynamics developed for a helicopter, a new trim method is pro- posed by coupling the model with the computational fluid dynamics （CFD） method in forward flight. In order to enhance the calculation precision of aerodynamic forces on aerodynamic components, such as rotor, fuselage, tail-rotor, etc., and re- duce dependency on test data, a CFD model based on Navier-Stokes equations is established which includes rotor and tail- rotor momentum sources. Grids around the helicopter are generated by using unstructured grids technology. Jameson central- difference scheme is adopted in spatial discretization and the five-step Runge-Kutta method is used for temporal discretiza- tion. Artificial viscosity is added to overcome numerical oscillation of solutions. Local time step method and variable coeffi- cient implicit residual smoothing method are used to accelerate the convergence for the helicopter flowfield. A high-efficient coupling strategy for trimming calculation coupled with CFD method is put forward by coupling the aerodynamic force from the CFD model with that from the flight dynamics model. Then the trim calculations are conducted by taking UH-60A helicopter as a numerical example on the basis of the flight dynamics model and CFD method validations. Special analysis on the precision and convergence rate of the present trim method is performed. It is demonstrated that the trim method can effectively im- prove trim analysis precision and meet engineering analysis requirements.