结构误差对旋转稳定弹丸气动特性影响的数值模拟

Numerical simulation of a spinning stabilized projectile aerodynamic characteristics effected by structure errors

  • 摘要: 基于剪切应力传输(SST) k-ω湍流模型,对考虑结构误差情况下的弹箭模型进行数值模拟计算。首先采用CFD和工程经验公式相结合的方法,得到了不同马赫数、不同转速情况下无结构误差模型的多种气动特性参数。通过与实验数据对比,阻力、法向力、俯仰力矩、压心位置误差在10%以内,验证了该方法的可行性和准确性。然后,建立了考虑结构误差即质量分布不对称、弹体不同轴和无结构误差模型,并分别进行了气动特性模拟计算。结果表明,质量偏心对滚转阻尼力矩系数、马格努斯力矩系数影响很大;弹体不同轴对法向力系数导数、俯仰力矩系数导数、马格努斯力矩系数导数和压心位置都产生很大影响。结构误差使模型的多种气动特性参数产生很大变化,将影响其飞行弹道和稳定性。

     

    Abstract: Based on the (Shear Stress Transport) SST k-ω turbulent model, the effets of vehicle′s model with structure errors are investigated using computational fluid dynamic (CFD) method. Firstly, the aerodynamic coefficients of the model without structure errors are calculated in the conditions of different Mach numbers and spinning speeds, and the results are compared with that of the experimental data. CFD calculations predicted the drag, normal force, pitching moment, and normal force center of pressure very well, and their errors are within 10% of the experimental data which verified the accuracy and feasibility of the CFD output. Then, the models without structure errors and the models with structure errors including projectile′s mass asymmetry and coaxial error are established, and their aerodynamic characteristics are numerically calculated by CFD. The results shown that the model of mass asymmetry have a great influence on its roll damping coefficient and magnus moment coefficient derivative, and the model with coaxial error have a great influence on its normal force coefficient derivative, pitching moment coefficient derivative, magnus moment coefficient derivative and center of pressure location. Projectiles′ aerodynamic characteristics coefficients may have a prodigious change due to structure errors, and the flight stability of the model may be effected by these coefficients′ prodigious change. The flight trajectory and stability also will be affected accordingly.

     

/

返回文章
返回