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一、高超声速湍流边界层研究的重要性随着再入导弹武器从惯性弹道导弹发展到可作机动飞行的多弹头分导弹道导弹,以及航天飞机的出现,高超声速再入飞行器的气动外形变得更复杂了。由于出现了多个激波的相互干扰,激波与边界层的相互影响,以及边界层的分离(入射激波和后台阶产生 相似文献
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在河道动力学中,一般在讨论泥沙和水的相对速度时,都应用斯笃克斯公式。但是这样一个假定是没有经过严格证明的,它的正确性必须仔细地加以讨论。本文根据流体力学的基本理论讨论了一个小球在不均匀流场中运动时候的情况。在讨论的时候,我们引进了两个基本假定:(1)圆球直径和流场的线性尺度比较起来小得很多;(2)水和圆球的相对速度很小。有了这两个假定以后,我们就可以把运动方程式线性化,然后再利用拉普拉斯转换找出线性化以后的方程式的解。最后得到小球在非均匀流场中运动时所受到的阻力。 相似文献
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When Bingham fluid is in motion, plugged flow often occurs at places far from theboundary walls. As there is not a decisive formula of constitutive relation for plugged flow,in some problems the solutions obtained may be indefinite. In this paper, annular flow andpipe flow are discussed,and unique solution is obtained in each case by utilizing the analyticproperty of shear stress. The solutions are identical in form with the commonly usedformula for the pressure drop of mud flow in petroleum engineering. 相似文献
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一九八二年八月二十八日,周培源教授度过了他的八十寿辰.从一九二九年在清华大学任教开始,到现在已经整整五十五个年头了.周老师为祖国培养了大批的人才,如王竹溪、彭桓武、林家翘、胡宁等人都成了著名的科学家.周老师在国内和国际的教育界、科 相似文献
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Here, we are discussing the applicable ranges of one-equation and two-equationturbulence models with the viewpoint of similar theory. The criterions of determining theapplicable ranges of these models are given. 相似文献
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Many studies on cavitation phenomena were based on the theoryof single bubble motion which was first put forward by Rayleighin his1917 article and later developed by plesset et al.Bythis theory,only some effects of forces were taken into conside.ration from hydrodynamics leaving out any thermodynamical effectssuch as matter interchange between liquid and gaseous phases.Strictly speaking,the theory may be suitable for discussing ex-pansion or/and contraction motion of a bubble formed in liquid,but this theory does not cpoe with cavitation behaviors in general.In this paper,the cavitation conditions and similarity problemsare discussed with thermodynamic effects taken into considerationin addition to the hydrodynamic ones. 相似文献
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湍流相干结构的机理研究(Ⅱ)——粗糙壁边界层相干结构的物理模型 总被引:2,自引:1,他引:1
本文主要分析了粗糙壁面相干结构的特性以及与光滑壁面相干结构的区别,讨论了从光滑壁到粗糙壁过渡的问题,在此基础上建立了粗糙壁面相干结构的物理模型,从理论上得到了慢条宽度、猝发时间等物理量与动量厚度雷诺数的关系,其结果与实验结果是相符合的。 相似文献
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