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Unsteady effect of seriously separated flow is the main factor of modern aircraft buffeting. So accurate simulation of this complex flow becomes the basis associated with the research of aircraft buffeting. This paper constructs an unsteady numerical simulation method for separation flow based on modified delayed detached eddy simulation (MDDES) method by considering both modern computer resources and the credibility of simulating separation flow. The proposed method is also verified through the simulation of the separated flow by a typical fighter at high angle of attack. And then a robust and efficient technology for deforming mesh is established using radial basis function (RBF) and infinite interpolation method. Moreover, the platform for numerical simulation of buffeting is set up in combination with the structural dynamics equations in the modal space, by which the research of vertical tail buffeting caused by edge vortex is carried out on a fighter at large angle of attack. Through spectrum analysis of time-domain response of pressure pulsation on the location of vortex rupture, the results show that the pulsation frequency of vortex structure with different scales covers the inherent modal frequency of vertical tail structure. Compared to the Reynolds-averaged Navier-Stokes equations, the MDDES method can distinguish the more detailed and higher frequency small-scale vortex structure. Unlike flutter, displacement acceleration response of each mode in buffeting is dominated by its own mode. There exists strong coupling between the first bending mode and first torsion mode, and it leads to acceleration and large inertia impact of structure, which is the main factor causing structural fatigue. In sum, the obtained results verify the validity of the numerical means and the corresponding methods in the paper. 相似文献
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在努力降低供水系统能耗的同时,提出一个能有效衡量能耗合理性的指标是很重要的.我国现有的单位耗电量指标及综合单位耗电量指标在考核供水系统整体能耗合理性方面缺乏横向可比性.针对这一情况,在分析供水系统输水所需最小能量的基础上提出功效性指标,并通过对该指标的分析,证明该指标具有对不同供水系统整体能耗情况进行对比的功能. 相似文献
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本文提出了一种新型的光学扫描方法 ,应用半导体激光器和线阵CCD实现了材料在拉伸过程中径向收缩量的在线检测 ,介绍了系统的工作原理和硬件处理方法 ,对影响测量结果的因素进行了分析 相似文献
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针对基本遗传算法在优化设计中遇到的局部搜索能力不强、早熟收敛等问题,提出一种将Powell搜索方法与遗传算法相结合的混合遗传算法。数值计算表明,该混合遗传算法可以有效地克服基本遗传算法的上述缺陷,可以加速算法的收敛,具有良好的优化性能。并使用该算法较好地解决了桥式起重机箱形主梁的优化设计。 相似文献
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基于Web的流体热物性远程计算系统研究 总被引:1,自引:0,他引:1
通过对当前流体热物性数据库的调查,结合课题组已有的研究基础,开发了一套基于Web的流体热物性远程计算系统。本文着重说明该系统的实现方法、主要模块及功能。该计算系统的研究,可为能源、动力、空调制冷及化工等领域的研究人员和工程技术人员获取流体热物性数据提供方便且有效的网络工具。 相似文献
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介绍了城市给水厂污泥组成、处理工艺、污泥脱水机能耗,对给水污泥处理技术发展及污泥的综合利用进行了评价;首次提出了水厂排泥水回用节约电耗计算公式和经济效益计算公式,给出了算例,为水厂排泥水处理技术的应用提供了电耗方面的经济评价依据。 相似文献
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介绍了城市给水厂污泥组成、处理工艺、污泥脱水机能耗,对给水污泥处理技术发展及污泥的综合利用进行了评价;首次提出了水厂排泥水回用节约电耗计算公式和经济效益计算公式,给出了算例,为水厂排泥水处理技术的应用提供了电耗方面的经济评价依据. 相似文献
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