小长径比弹丸加装大展弦比尾翼的气动特性研究

为了提高小长径比弹丸射击质量,设计了一种大展弦比张开式尾翼,采用AUSM+格式、SST(shearstress transport)湍流模型和隐式算法(lower-upper symmetric Gauss-Seidel implicit method, LU-SGS),求解三维RANS 方程,对前体形状完全相同,不同展弦比的3 种尾翼弹进行了数值模拟,得到了三者在马赫数1.5~3.5 下的气动力特性的差异,分析其原因,并给出了不同展弦比张开式尾翼的适用范围. 计算结果表明:C型弹的升阻比较B 型弹在1.5 马赫数区域附近增加了7% 以上,当马赫数达到2.5 以上时,A 型弹的升阻比大于B 型弹和C 型弹,在3.5 马赫数区域附近A 型弹的升阻比较B 型弹增加了5.4% 以上. 3 种弹丸的俯仰力矩系数随着马赫数的增大而负向减少,且减少的趋势随着展弦比的增加而增大. A 型弹、B 型弹、C 型弹的静稳定裕度的变化范围分别为4%~20.3%,8.5%~23.2%,11.4%~25.6%.

AERODYNAMIC CHARACTERISTICS OF FIN-STABILIZED SHELL OF HIGH ASPECT RATIO AND SMALL LENGTH-DIAMETER RATIO

A flip-out tail fin is designed to improve the shooting quality of the fin-stabilized shell of small length-diameter ratio. Three fin-stabilized shells with fins of the same shape and different aspect radios are simulated numerically by applying the AUSM+scheme. The shear stress transport turbulence models and the lower-upper symmetric Gauss-Seidel implicit method are used to solve the 3D Reynolds-averaged Navier-Stokes equations. The differences in the aerodynamic coefficients and the aerodynamic characterstics of the projectiles when the Mach number varies from 1.5 to 3.5 are obtained and analyzed, and the applicability of fins of different aspect radios is discussed. The calculation results indicate that the lift-to-drag ratio of the C-type shell is 7% greater than that of the B-type shell in the region where the Mach number is close to 1.5; as the Mach number is above 2.5, the lift-to-drag ratio of the A-type shell is greater than that of the B-type shell and the C-type shell; the lift-to-drag ratio of the A-type shell is 5.4% greater than that of the B-type shell in the region where the Mach number is close to 3.5. The pitching moment coefficient rises in absolute value when the Mach number gradually increases, the rising trend increases with the increase of of the aspect ratio. The static stability variation ranges of the A-type shell, the B-type shell and the C-type shell are 4%~20.3%, 8.5%~23.2% and 11.4%~25.6%, respectively.