三角翼大迎角风洞试验支架干扰数值模拟研究

现代战争要求战斗机能够在大迎角（AOA）状态下进行过失速飞行，对飞机大迎角绕流流场的研究主要的方法有风洞试验和数值模拟。在大迎角风洞试验中，常用的是尾支撑方法，支架的存在会对模型的试验结果产生一定的影响，本文通过数值模拟来对这个影响进行研究。以开源计算流体力学软件OpenFOAM 2.3为平台，采用PIMPLE算法求解Navier-Stokes（N-S）方程，PIMPLE算法是SIMPLE（Semi-Implicit Method for Pressure-linked Equations）算法和PISO（Pressure Implicit with Splitting of Operator）算法的结合体；采用基于有限体积的空间离散方法和空间二阶精度的线性插值方法，时间离散采用后向差分方法，湍流模型采用SA-DDES（Spalart-Allmaras-Delayed Detached Eddy Simulation）模型。为了验证方法的可靠性，首先对0°、10°、30°、50°、70°以及90°迎角下的有支架三角翼绕流流场进行计算，并将计算结果与试验结果进行对比，两者吻合较好。在此基础上，数值模拟了无支架的三角翼绕流流场，对比有/无支架情况下数值模拟结果，得到支架对三角翼绕流流场、背风面压强分布和气动力的影响。计算结果表明：大迎角情况下，有支架与无支架时相比，支架的存在会影响三角翼附近的流场（但是不会改变涡系等流动结构）、改变翼表面压强分布，从而导致三角翼的法向力系数和俯仰力矩系数发生明显变化。

Numerical simulation investigation of aerodynamic interference of sting support in wind tunnel test of a delta wing at big angles of attack

In current wars, the fighter is required to be capable of stalled flight at a high angle of attack (AOA). The investigation of the aerodynamic characteristics of the aircraft mainly relies on wind tunnel test and numerical simulation. In the wind tunnel test of high angle of attack, the commonly used method is to use sting support. The presence of the sting support can have an effect on the model testing results which will be numerically investigated in the present paper. The open source software package OpenFOAM 2.3 is used as computational fluid dynamics (CFD) computing platform, the PIMPLE algorithm is applied to solving Navier-Stokes (N-S) equations. The PIMPLE algorithm is a combination of both semi-implicit method for pressure-linked equations (SIMPLE) and pressure implicit with splitting of operator (PISO). A finite volume method is used for spatial discretization. Second order linear interpolation is also adopted. Backward differentiation method is to deal with time discretization. The employed turbulence model is Spalart-Allmaras-delayed detached eddy simulation (SA-DDES). In order to verify the reliability of the numerical method, the flow filed of the delta wing with sting support is computed at angles of attack of 0°, 10°, 30°, 50°, 70°, and 90° firstly. The obtained results are compared to the testing data and they are in close agreement. After that, the numerical simulation of the flow field of the delta wing without sting support is executed. The influence of the sting support on the flow filed, pressure coefficient distribution on the leeward side and aerodynamic coefficient is obtained through comparing the numerical results with and without sting support. In contrast to the situation without the sting support, at a high angle of attack, the presence of the sting support affects the flow field around the delta wing (but does not change the vortices and flow structure) and alters the pressure coefficient distribution on the wing leeward side. Therefore, normal force and pitching moment coefficients have significant changes.