Comparing with the neutral cave on the smooth plane that was thumb - like and opened at the bottom , the neutral caves on the plane with single roughness elements were closed circles . with the growing of roughness element s height , the closed circle became smaller 实验中发现与光滑平板边界层的下端开放式的拇指型中性曲线相比较，有粗糙元平板的中性曲线为封闭式的环形曲线，随着粗糙元高度的进一步增加中性曲线收缩为更小的闭合环。
In this model , the velocity was controlled below50 m / s so that it is easy that the temperature of outlet propellant exceeds 1000k . by the measure of advancing the melting point of metal panel to 3000k , the temperature of outlet propellant even could be close to the very high temperature of the metal panel . it is very active to improve the capability of the whole propulsion system 在本文模型中,将管道内工质的流速控制在50m / s ,热交换器的出口工质温度就能够提升至1000k以上;提高换热器高温加热段的金属平板熔点到3000k以上,完全可以将工质出口温度提升至接近金属平板的温度,这样可以大幅度提高推进系统的性能。
As regards to the spheric thin shell structure under external hydro static pressure , basing on flat - plate theory and by using basic von karman equations for large deflection , the equilibrium problem of axisymmetric bending of the spheric shell under uniform external pressure is simplified to an equilibrium problem of bending of elastic basic flat - plate and further converted into an equilibrium problem of beam on elastic fundation taking into consideration of the deformation characteristics 对球形薄壳结构随静水外压的情况，应用平板理论中的vonkarman大挠度基本方程，将球形薄壳在均匀外压下的轴对称弯曲平衡问题简化为弹性基础平板的弯曲平衡问题，进而再根据变形特点将其转化为弹性基础梁的复杂弯曲平衡问题。
Comparing its results with those by ls - d yna , the accuracy of this algorithm was presented . moreover the failure process in concrete due to impact loading and the failure process of a steel bullet penetrating a concrete circular plane was demonstrated , which presented the dynamic transitional process from continuum to non - continuum . several different fundamental damage forms simulated by using this algorithm were discussed , comparing with the results from experiments 应用该模型对正交各向异性平板内的应力波传播、冲击载荷下混凝土平板的破坏以及钢弹侵彻混凝土圆板的破坏问题进行了研究，通过将计算结果与ls - dyna 、特征线法以及实验结果进行对比，证明了该模型的精确性和可靠性。
The purpose of this thesis is to use artificial neural networks ( ann ) to identify the aerodynamic parameters . first introduced in this paper is the basic theory of ann and wind engineering in bridge , then ann is presented to identify the aerodynamic derivatives of ideal thin plate . a back - propagation ( bp ) ann is established and trained for many times to contrast the influences of some factors on the prediction results 首先对人工神经网络和桥梁风工程的基本理论作了简单的介绍，接着采用人工神经网络识别了理想薄平板的气动导数，并分析了数据处理方式、隐层单元数、训练次数、随机赋值次数、样本数量对训练结果的影响，讨论了训练的稳定性。
An experimental investigation on the transition in the boundary layer of horizontal plane with and without single two - dimensional roughness elements has been carried out in the wind tunnel . the distribution in normal and stream - wise directions of intensity of t - s wave excited by vibrating beam was measured in every condition . neutral curves were obtained by measuring the growth of the t - s wave at the normal critical location along the stream - wise direction 在风洞中对水平光滑平板以及加有粗糙元平板的边界层转捩进行了测量与研究，比较了不同情况下平板边界层内由振动梁激励生成的t - s波沿流向和法向强度的分布规律，得到了相应的振型增长曲线以及中性曲线。
Based on the predecessors " work , this paper organized the following work centered around experimental research on and theoretical analysis of prestressed concrete slabs with openings : firstly , the writer performed experiment with three slabs with openings , and made comparison with predecessors " work 本文在前人工作的基础上，围绕预应力混凝土开孔平板的实验研究和理论分析，开展了如下工作：首先，对预应力混凝土开孔平板进行了实验研究。笔者进行了三块板的实验，然后结合前人做的实验数据进行比较分析。
