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为了深入分析风洞试验中来流参数的扰动对翼型气动试验结果的影响,基于雷诺平均Navier-Stokes方程有限体积方法,采用Spalart-Allmaras湍流模型,发展了一套二维计算流体力学(CFD)程序,应用自动微分方法对CFD程序进行改造,建立了对应过程的敏感性导数计算方法和程序,可以一次性获得翼型各处压力系数和所有气动力系数对迎角、马赫数和雷诺数的敏感性导数。研究结果表明:在亚声速和跨声速中,翼型压力分布对马赫数最敏感,比对雷诺数的敏感性至少高8个量级,但是,在亚声速来流中,翼型压力系数的不确定性由迎角摄动引起的部分比马赫数摄动引起的部分高1个量级,迎角控制精度很大程度上决定了风洞试验结果的精度;在跨声速来流中,迎角摄动引起的不确定性比马赫数摄动引起的要低1个量级,同时,对马赫数敏感性的增强使得翼型压力分布的不确定性在跨声速范围比在亚声速范围高1个量级,此时马赫数的控制精度很大程度上决定了风洞试验结果的精度。
In order to further analyze the influence of the disturbance of the flow parameters on the aerodynamic test results of the airfoil in the wind tunnel test, based on the finite volume method of the Reynolds-averaged Navier-Stokes equations and the Spalart-Allmaras turbulence model, a set of two-dimensional computational fluid dynamics (CFD ) Program, the automatic differential method is used to transform the CFD program, and the sensitive derivative calculation method and program of the corresponding process are established. The pressure coefficient and all aerodynamic coefficients of the airfoil at all angles can be obtained once and for all at the angles of attack, Mach number and Reynolds number Sensitivity derivative. The results show that in the subsonic and transonic speeds, the airfoil pressure distribution is the most sensitive to the Mach number and at least eight orders of magnitude higher than the Reynolds number. However, in subsonic flow, the airfoil pressure coefficient The uncertainty caused by the perturbation of the angle of attack is one order of magnitude higher than that caused by Mach number perturbation. The accuracy of the attack control determines the accuracy of wind tunnel test results to a great extent. In the transonic flow, The uncertainty caused by angular perturbation is one order of magnitude lower than that caused by perturbation of Mach number. Meanwhile, the sensitivity to Mach number makes the uncertainty of airfoil pressure distribution higher in transonic range than in subsonic range 1 order of magnitude, at this time the Mach number control accuracy largely determines the accuracy of wind tunnel test results.