排序方式: 共有9条查询结果,搜索用时 12 毫秒
1
2.
基于欧拉-欧拉双流体模型对通气空泡尾部气泡流进行数值仿真, 并采用基于多尺寸分组模型的总体平衡方法预估气泡尺寸分布. 应用改进后湍流耗散系数计算模型, 考虑了气泡体积含量对在湍流作用下气泡扩散现象的影响. 基于上述模型对两种试验工况下流场进行了数值仿真.结果表明模型对空泡尾部回流区特性进行了准确预示, 在回流区高湍流度作用下气泡迅速破碎成小气泡. 并进一步得到试验体尾流区空泡体积分数和速度分布. 尾流区水流速度分布保持了流体经过非流线型对称体时产生的尾流分布规律. 仿真结果与试验数据相一致, 模型适用性得到验证. 相似文献
3.
4.
5.
6.
建立了主动式雷达制导对抗仿真系统,在仿真的基础上,对影响决策的各种对抗条件的物理意义和影响过程进行了分析;建立了基于统计的箔条对抗平均成功概率模型,提出了一种干扰布放决策寻求方法,有效地实现了雷达对抗最优化策略的求解。最后在仿真平台上进行大量的测试,对预估结果进行了分析,验证了仿真模型和决策分析方法的正确性。 相似文献
7.
8.
Unsteady wake from upstream components of landing gear impinging on downstream components could be a strong noise source.The use of a plane jet is proposed to reduce this flow-induced noise.Tandem rods with different gap widths were utilized as the test body.Both acoustic and aerodynamic tests were conducted in order to validate this technique.Acoustic test results proved that overall noise emission from tandem rods could be lowered and tonal noise could be removed with use of the plane jet.However,when the plane jet was turned on,in some frequency range it could be the subsequent main contributor instead of tandem rods to total noise emission whilst in some frequency range rods could still be the main contributor.Moreover,aerodynamic tests fundamentally studied explanations for the noise reduction.Specifically,not only impinging speed to rods but speed and turbulence level to the top edge of the rear rod could be diminished by the upstream plane jet.Consequently,the vortex shedding induced by the rear rod was reduced,which was confirmed by the speed,Reynolds stress as well as the velocity fluctuation spectral measured in its wake.This study confirmed the potential use of a plane jet towards landing gear noise reduction. 相似文献
9.
基于助推段红外辐射特性的SBIRS探测能力分析 总被引:1,自引:0,他引:1
天基红外系统(SBIRS)是美导弹防御系统的重要一环,能对助推段的进攻弹进行预警和弹道预报。在红外探测器工作原理的基础上,建立了主动段发动机喷管辐射、蒙皮辐射、尾焰辐射和背景辐射的模型,推导了总辐射亮度的计算公式,分析了SBIRS的探测距离。 相似文献
1