复杂流场的非定常气动力计算以及气动弹性研究

【作者】 梁强；

【导师】 杨永年；

【作者基本信息】 西北工业大学 ， 流体力学， 2003， 博士

【摘要】 本文的主要工作是利用计算流体力学(CFD)方法，数值模拟机翼和全机的定常及非定常粘性绕流，并在此基础上耦合结构动力学方程研究了飞行器的多种气动弹性问题。最后对以上气动弹性问题的数值计算进行了基于微机网络的分布式并行计算研究。 利用代数无限插值方法，生成适合非定常有粘流动计算用的贴体运动结构网格，从三维非定常Navier-Stokes方程组出发，采用LU-NND有限差分格式和Baldwin-Lomax湍流模型建立了一种数值模拟三维机翼和全机的亚、跨、超音速定常及非定常粘性绕流的计算方法和程序。在模拟定常粘性绕流的基础上，耦合结构静平衡方程，对机翼的静气动弹性问题进行了研究，并在此基础上创新性地提出了多学科、多目标的型架外形优化设计和飞行姿态确定方案。在模拟非定常粘性绕流的基础上，与颤振运动方程相耦合，分别对机翼和全机流固耦合现象中颤振问题进行了研究，准确求解跨音速颤振临界速度，分析机翼和全机的从亚音速到超音速范围的颤振规律，并研究分析了机翼飞行迎角变化对颤振速度的影响。 利用现有条件自主开发出适合定常、非定常流场计算和气动弹性研究的分布式并行计算机系统。通过对单机串行程序进行分布式并行化改造，在国内首次实现了基于微机网络上的静气动弹性和颤振分布式并行计算，解决了数值求解气动弹性问题难以避免的耗时巨大的问题。 以多种机翼和某歼击机为算例，分别对其定常及非定常粘性绕流进行了数值模拟。分别以某后掠机翼和超临界机翼为算例，对机翼的静气动弹性问题以及基于静气动弹性的型架外形优化设计和飞行姿态确定进行研究，计算结果和有关文献的结果进行了比较，吻合很好。对多个机翼和导弹舵面的亚、跨、超音速的颤振特性进行了数值计算，求解从亚音速到超音速多个马赫数下的颤振基于微机网络的分布式并行计算机上，对多个机翼和全机算例进行了分布式并行计算，并对各个算例的并行和串行程序的计算结果和计算速度进行比较，验证分布式并行计算求解复杂非定常流场的可行性和高效性，对比分析发现，分布式并行计算可以在不影响计算精度的前提下，大大提高计算速度，是一种提高CFD运算效率的理想方法。更多还原

【Abstract】 The research of this dissertation is focused on how to simulate numerically the steady and unsteady subsonic, transonic and supersonic viscous flows around wing and aircraft by computational fluid dynamics method. On this basis, several kinds of aeroelastic problems of aircraft are investigated. Finally for all the above aeroelastic problems, distributed parallel computation is accomplished.The body-Fitted viscous moving mesh for unsteady flow is generated by algebraic finite integration. Then the steady and unsteady subsonic, transonic and supersonic viscous flows around airfoil and some aircraft are numerically simulated. The 3-dimensional unsteady Navier-Stokes equations are solved using the implicit LU-NND algorithm, with Baldwin-Lomax turbulent model. On the basis of simulating unsteady viscous flow, coupling the structure dynamics equations, the problems of static aeroelasticity and flutter are investigated for wings and elevator. Basing on the static aeroelasticity, the jig-shape and the attack angle design have been studied.Generally, much computing time is needed in unsteady flow computation. In order to reduce the computing time and improve efficiency, the procedure has been paralleled and the distributed parallel computation is accomplished in a net with four PCs. The parallel computation of static aeroelasticity and flutter has been initiated at home.On this basis, the work includes four parts. Firstly, many examples, simulating the steady and unsteady viscous flows around several wings and some aircraft, are given in this paper. Secondly, the static aeroelastic problems and jig-shape design, as a kind of Multi-disciplinary Design Optimization (MDO), are investigated for sweep wing and super-critical wing. Numerical results are in good agreement with otherreference data. The method and the program presented in this paper are verified. Thirdly, the subsonic, transonic and supersonic flutter critical speed of wings and aircraft is numerically simulated. Some numerical results are in good agreement with experimental data. Fourthly, the numerical results and computing speed of the series program and the parallel program are compared in this paper. It indicates the feasibility and the efficiency of the distributed parallel computation in solving complicated unsteady flows. That means, as a good numerical method, distributed parallel computation can improve computing speed greatly in the same accuracy.更多还原