降落伞稳降阶段的SPH方法数值模拟

发布时间：2018-05-11 09:31

  本文选题：下降过程 + 流固耦合　； 参考：《航天返回与遥感》2016年03期

【摘要】：随着计算机技术的不断发展以及数值模拟技术的兴起,对降落伞力学特性的模拟日益精确。为了消除传统降落伞模拟中因网格大变形而产生负体积的影响,文章采用光滑粒子流体动力学方法,对选定降落伞模型开展了稳降阶段的流固耦合数值模拟,计算得到的气动力系数与风洞试验结果较为一致。研究了空气粒子密度对数值结果的影响,结果表明,粒子密度过少,降落伞结构单元难以和流场实现有效耦合,计算精度降低;但粒子密度超过一定值,不仅会增加计算消耗,也会增加舍入误差而影响计算精度,确定了最佳粒子数。在此基础上,模拟了不同初速度下降落伞的下降过程,获得了降落伞外形、投影直径、下降速度、降落伞气动力及伞衣摆角的动态变化情况。数值结果表明伞衣的呼吸频率、稳定后的平衡速度和气动力受速度影响较小,但速度增加,伞衣呼吸强度及摆角增加,且摆动角度的衰减性要低于投影直径的衰减能力。SPH模拟方法有效地回避了降落伞流固耦合的网格大变形问题,在柔性大变形流固耦合问题上有广阔的应用前景。
[Abstract]:With the development of computer technology and the rise of numerical simulation technology, the simulation of parachute mechanical characteristics is becoming more and more accurate. In order to eliminate the negative volume effect caused by large mesh deformation in the traditional parachute simulation, the fluid-solid coupling numerical simulation of the selected parachute model is carried out by using the smooth particle hydrodynamics method. The calculated aerodynamic coefficients are in good agreement with the wind tunnel test results. The effect of air particle density on the numerical results is studied. The results show that if the particle density is too small, it is difficult for parachute structure elements to be effectively coupled with the flow field, and the calculation accuracy is reduced, but if the particle density exceeds a certain value, the computational consumption will not only increase. The rounding error will also affect the accuracy of the calculation and determine the optimum number of particles. On this basis, the descent process of parachute at different initial velocities is simulated, and the dynamic changes of parachute shape, projection diameter, descent velocity, parachute aerodynamic force and yaw angle of parachute coat are obtained. The numerical results show that the respiration frequency, equilibrium velocity and aerodynamic force of the canopy are less affected by the velocity, but the velocity increases, and the respiration intensity and swing angle increase. Moreover, the attenuation of swing angle is lower than that of projection diameter. SPH simulation method effectively avoids the problem of large grid deformation of parachute fluid-solid coupling, and has a broad application prospect in flexible large deformation fluid-solid coupling problem.
【作者单位】： 南京航空航天大学航空宇航学院;
【基金】：国家自然科学基金(11172137)资助项目 江苏高校优势学科建设工程资助项目(PAPD) 南京航空航天大学研究生创新基地(实验室)开放基金资助(kfjj20150104-01) 中央高校基本科研业务费专项资金资助
【分类号】：V445.23
，

本文编号：1873396