基于时态自适应湍流模式与伴随方法的螺旋桨飞行器气动设计方法研究

The propeller-driven aircrafts are one of the most important configurations for military and civil aircrafts, and their aerodynamic shape design usually needs to take a host of factors into consideration. For example, the turbulent simulation methods, fluid mechanics, optimized design methods and so on. Hence, the work for developing a comprehensive design method with high precision and efficiency for propeller-driven aircrafts is still in early stages due to its complexity. This project intends to build a high efficient design approach based on the combination of developing a uniform turbulence model for steady and unsteady flows and building a gradient-based adjoint optimized system. The procedure of all work will start from the turbulence modelling which is the basic problem of computational fluid dynamics. The project will be carried out by three issues：（1）The time-state-adaptive turbulent time or length scale which is grid-independent and scale-adaptive will be built. Then, the new time-state-adaptive turbulence model which is very suitable for the all regions of the flight envelope of the propeller-driven aircrafts will be constructed. (2) The developed process of propeller-wing interference will be analyzed and then the internal relation between the control parameters of the configuration of propeller-driven aircraft and the propeller-wing interference intensity will be revealed. This work will be helpful for obtaining the key design variables. (3) A high precise and efficient designed approach for propeller-driven aircrafts will be constructed based on the new turbulence model and adjoint method. The final approach will be validated on an aerodynamic optimized design of a realistic three-dimensional propeller-driven aircraft.

螺旋桨飞行器是军民用飞行器的重要布局形式，其气动设计需要综合考虑湍流模拟方法、流动机理以及优化设计方法等众多因素，将这些因素综合考虑而进行螺旋桨飞行器的高效高精度气动设计方法研究多数仍处于起步阶段。本项目以湍流建模这一计算流体力学基本问题为切入点，建立定常与非定常统一的湍流求解模式，构造梯度伴随优化系统，建立一种高效的螺旋桨飞行器气动布局设计新模式。本项目拟从三个方面开展研究：（1）构造时态自适应的湍流长度或时间尺度，挖掘网格对于湍流脉动解析的最大潜力，以此建立适于螺旋桨飞行器飞行包线全区域的高精度湍流模式；（2）分析桨-翼干扰演化的物理过程，揭示螺旋桨飞行器布局控制参数与桨-翼干扰强度之间的内在联系，从而提取合适的设计变量；（3）基于伴随方法与新湍流模式相结合，建立高效高精度的螺旋桨飞行器气动优化设计方法，以真实螺旋桨飞机气动设计为算例，考核优化方法的实用性。

伴随气动优化是一种实用性很高的气动优化设计方法，可以有效适应计算变量较多时的气动优化问题。本项目以湍流建模这一基本的入手点，将旋转率修正与气动伴随方程相结合，发展了两种两方程湍流模型，分别对非平衡流动、旋转流动以及粗糙表面流动建立了统一求解模型。在此基础上，推导出了旋转坐标系下的流场伴随方程，拓展了现有的气动伴随方法。基于理论方程，完成了旋转坐标系气动伴随优化平台的搭建，并将其应用到了实际的螺旋桨设计中，增强了气动伴随方法的实用性，扩展了气动伴随方法的适用场景。