声速

The absolute/convective instability of incompressible swirling flows and the temporalinstability of compressible swirling flows have been fully explored, whereas the absolute/convectiveinstability of compressible swirling fl.

从N－S方程出发，通过正则模方法，研究了超声速尾涡的绝对／对流不稳定性性质。

It mainly studys the relations of upriver absolute pressure and flow, the relations of differential pressure and flow, the influence of testing pipe to the result.

主要研究了上游绝对压力与流量的关系，差压与流量的关系，声速流导和临界压力比与上游压力的关系，测试管对测试结果的影响等。

The influence of radiation on flow was controlled by temperature and absorption coefficient.

结合流动计算的MacCormack格式和辐射传输计算的Monte Carlo法，研究了跨声速喷管内流动与辐射的耦合现象，考察了不同温度和吸收系数情况下流动与辐射的相互影响。

This method is based on the Snell law of acoustic propagation in water. Different velocity gradients among linear layers in water are utilized to draw the sound ray chart, and a mathematical model of the geometric operational range is built. Furthermore, the geometric homing range is predicted with sound ray density, a prediction system of geometric operational range for acoustic homing torpedo is designed and the function of the system is realized through a system software. The sea trial demonstrates the prediction validity of the system.

该方法基于声波在水中传播的Snell定律，利用水中各线性分层间不同的声速梯度，绘制声线图，建立了几何自导作用距离的数学模型，并通过声线密度对几何作用距离进行预报，设计了声自导鱼雷几何作用距离预报系统，并通过系统软件实现了其功能，经测试，该系统在海上试验中取得了良好效果。

Firstly, studies for hypersonic inlets are reviewed, including issues related to interaction between boundary and shock wave in hypersonic inlet, unstarting/restarting phenomena, isolator, boundary bleeding for hypersonic inlet, internal/external compression ratio for inlet, inlets with sidewall compression, etc..

首先是高超声速进气道的研究进展，包括高超声速进气道中激波与附面层干扰、起动和再起动、隔离段、进气道附面层抽吸、进气道通道内外压缩比、侧压式进气道、Busemann进气道等。

The results show that for a supersonic shear layer without reaction, a disturbance can make the shear layer become unstable, this results in one vortex or more than one vortex. The combination and seperation of vortex can intensify the mixing. But it is not easy for supersonic reacting shear layer with exotherm to become unstable with disturbance, and the effect duration is very long.

结果表明，对完全气体的超声速剪切层流动，一定的激励方式能使原先较为稳定的剪切层流动变得不稳定，产生单涡或多涡结构，发生多涡间的合并，使混合加剧；但对于存在放热现象的反应超声速剪切层流动，外加激励方式不易使流动从稳定变为不稳定，而且外加扰动的作用特征时间也较长，实际应用前景不乐观。

This paper described the principle of plane ultrasonic spreading abroad in the liquid coming into being ultrasonic grating,educed the density and refractive index changing rule basis continuity equation of not-ideal liquid and Lorentz-Lorenz law,expressing the transformation of the index and refractive index satisfaction similar equation of standing wave,and described the relation curve of the standing wave form at a few special times,liquid density and refractive index periodic variety according to the res...

描述了平面超声波在液体里传播形成超声光栅的原理；根据非理想流体对应的连续性方程和Lorentz-Lorenz定律，推导了液体光栅中液体密度与折射率的周期性变化规律，表明液体密度和折射率变化满足相似的驻波方程；根据推导的结果描绘了几个特殊时刻的驻波波形、液体密度、折射率周期性变化之间的关系曲线；进而由折射率周期性变化规律分析了超声驻波自身像的形成原理，并给出了CGS型超声光栅声速仪利用超声驻波自身像测量声速的方法与实验结果。

It is the first time to calculate the near noise field with ray method, and replace the inhomogenous SSP in the vertical direction with constant SSP, while other models usually use Fast Field Program such as SARFRI to calculate the near noise field. This model increases the calculation speed about 100 times without decreasing much precision. It can meet the need of engineering.

首次采用射线模型计算噪声近场的贡献，并进一步用等声速代替有垂直分布的声速剖面，而其他模型通常采用诸如SARFRI等快速场程序计算近场的贡献；本模型的计算时间比其他模型的计算时间缩短了2个数量级，精度并未有明显损失，适合工程需要。

In view that the combustion efficiency and flame stability are affected by the interaction of flow and combustion, further systematical research on phenomena and mechanism of the interaction between flow and combustion in supersonic combustors is needed.

由于流动与燃烧的相互作用直接影响超声速燃烧室中的燃烧效率与燃烧稳定性，因此有必要对超声速燃烧室中流动与燃烧的相互作用现象及其机理进一步开展系统深入的研究工作。

The influence of the size of sound lens and the sound velocity in sound lens material and crude oil and rock stratum on the sphere of action is studied.

分析了声透镜尺寸及材料中的声速、原油及岩层中的声速对其传播距离的影响。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。