飞机亚音速非对称运动流场数值计算

NUMERICAL COMPUTATION OF THE FLOWFIELD ABOUT AN AIRCRAFT WITH SUBSONIC SPEED AND NONSYMMETRIC MOTION

本文以飞机亚音速对称运动（仅小攻角）流场数值计算为基础，采用涡格法理论开发飞机亚音速非对称运动（小攻角、小侧滑角、小角速度）流场特性数值计算。本文特点：从毕－萨公式出发推导的涡格法流场诱速公式比面涡法简便；采用多坐标系，详细推导了各坐标系转换公式；将复杂的干扰流场简化为一阶干扰和二阶干扰效应，并仔细推导了相应的流场诱速计算公式。已在ＩＢＭ－４３４１计算机上建立了流场计算实用性程序，既可单独运算，也可联入我国外挂物投放／发射过程数值仿真系统（ＣＳＳＰ）串联运行，提供所需流场特性。以Ｊ－ＸＸ型号飞机和两个翼身组合作为算例，定性分析了非对称运动流场计算规律；将两个翼身组合体对称动动流场特性计算值与实验值进行了比较。飞机亚音速非对称运动流场特性计算比对称运动情况更为复杂，难度更大。该工作对进一步开发ＣＳＳＰ系统具有重要价值。

Based on the computation of the symmetric subsonicflowfiled past an aircraft(With low angle of attack only), a numerical technique using vortex-lattice method that analyzes the corresponding nonsyrnmetric flowfield characteristics(with low angles of attack and sideslip and low angular velocity) is developed.This paper features the simplicity and convenience of the induced velocity formula based on the Blot-Savar's law in the present vortexlattice method; the adoption of various coordinate systems and the detailed dcrivation of tile transformation matrices for different coordinate systems; the reduction of the complicated interference flowfield into first-and second-order interference effects with the corresponding formulas of the induced-velocity field.The practical flowfield computation program has been established on the IBM-4341 system, which can be run independently or incorporated into the numerical simulation system for the external store drop/ejection process(CSSP ) by providing the necessary flowfield characteristics. Taking the J=8Ⅱ fighter and two wing-body combinations as examples, the characteristics concerning the nonsymmetric flowfield computation are analyzed qualitatively, and the computed results of symmetric flowfield about the two combinations are compared with experimental data.The calculation of the nonsymmetric subsonic flowfiled about an aircraft is more complicated and more difficult than that in the symmetric case. The work finished here will be of great significance to the further development of the CSSP system.