波传播

At the same time, combining with the actual condition of delivery pipeline of our country and some prevalent leak detection and location methods, this paper raised a method, which is based on wavelet analysis and negative- pressure-wave to detect and locate the leakage. Jobs in the paper are as follows:As affected by gas density, pressure, specific heat and pipe material, the velocity of negative-pressure-wave improved depending on the energy conservation. At one time, taking the affection of velocity of gas flow, the location formula was modified in some degree.When locating the leaks with location formula, the iterative approach algorithm was adopted as a new method to increase the location accuracy level of system.Multi-scale decomposition and reconstruction of wavelet transform is utilized to filter the noise of negative-pressure-wave, which was brought by leakage. With the capacity to detect the signal singularity fast and accurately, wavelet transform was used to catch the break point of pressure signal. The work improved the accuracy of At in location formula, accordingly improved the location accuracy.Wavelet is a suitable tool for signal analysis. The distinct character is that the mother-wavelet is of optional. That means choosing different mother-wavelet will get different analysis result. So we studied how to choose mother-wavelet and its scale for signal singularity detection. The method is to choose a wavelet by regularities of the wavelet and the signal.Finally, a plan, which bases on SCADA system for inspection and detection of natural gas leakage, is proposed in the article.

其中，主要进行了以下几方面的工作：针对泄漏产生的负压波在管道中的传播速度受媒介的密度、压力、比热及材质等因素的影响，而非声波在空气中传播的速度，本文利用能量守恒原理，对其进行了修正；考虑到管内气体流速对压力波速的影响，对原始的负压波定位公式进行了一定程度的改进，并在利用定位公式进行泄漏点定位时采用逐步迭代逼近算法，提高了系统的定位精度；利用小波变换的多分辨率分解和重构技术，对采集到的管道发生泄漏时产生的负压波信号进行了降噪处理；并利用小波变换技术对信号奇异点的快速、准确的识别能力，对经上述消噪后的负压波信号进行了奇异点捕捉，精确捕捉的结果提高了定位公式中上下游站点采集到的负压波奇异点的时间差△t的精度，从而进一步提高了定位的精度；考虑到小波变换是一种基波可变的信号分析工具，也就是说，不同的小波基波对信号分析的结果将有很大差别，这势必影响最终的处理结果，因此，我们又对比分析了本课题中小波基及尺度的选择问题，依据规则性系数相似性原理对母小波的选择进行了探索性研究；最后，还提出了基于SCADA的泄漏检测与定位系统的软件开发构想及系统的嵌入方案。

The results of 3-D numerical modeling of the transversely isotropic media with horizontal symmetry axis and the orthorhombic symmetry media showed that quasi P wave,quasi-SV wave and quasi-SH wave occurred during elastic wave propagation in 3-D anisotropic media. Meanwhile, the special phenomena such as the S wave splitting, the blind zone of S wave splitting and quasi-SV wave-front triplication were clearly observed. In addition, the elastic wave-fronts are spatially changed, and the coupled relations among the quasi-P wave,quasi-SV wave and quasiSH wave in 3-D anisotropic media are very complex.

对方位各向异性介质模型和正交各向异性介质模型中弹性波的传播进行的三维数值模拟结果表明，弹性波在三维各向异性介质中传播时存在拟P波、拟SV波和拟SH波，并出现横波分裂、横波分裂盲区、波面三分叉等特殊现象，另外，性波场在空间是变化的，其拟P波、拟SV波和拟SH波的耦合关系比较复杂。

The results are verified from deep to extremely shallow water conditions. The shoaling waves, standing waves, 3D disturbance waves, tidal waves and solitude waves are simulated and verified,and waves over an underwater bar,the diffraction near single breakwater, breakwater gap, offshore breakwater, Breakhoff experiment are taken into account in this model. Furthermore, the wave harbor resonance under special topography, and "Bragg" resonance are simulated. The wave refraction problem under current fields,the nonlinear wave refraction-diffraction under "Arthur" current field, and the wave propagation under slowly varying current field are studied. The favorable calibrations show the model's feasibility in dealing with the wave nonlinearity and simulation in both deep and shallow water.

论文对深水至极浅水非线性波进行了较全面的验证，计算模拟了波浪浅化、立波、三维干涉波、潮波、孤立波以及波浪越过潜堤、单突堤绕射、双突堤绕射、岛式堤、Berkhoff实验和多连通水域波浪传播等问题，还对特殊地形条件下波浪发生港湾共振、布拉格共振进行了仿真；论文研究了水流中波浪传播折射变形问题，Arthur流场上非线性折射-绕射、水位缓变的转向潮流中波浪传播等缓变水流中波浪问题，各类问题的较好解决验证和表明了本文模式与方法具有适用于深浅水的可计算性与非线性。

For strong disturbance case in which Δp is set to be 5, by examining the distributions of relevant physical quantities along radial direction and the normal of wave front, we can infer that the slow wave introduced by the strong pressure pulse steepens into slow shock during the propagation process.

与二维情形类似，沿由源区出发的径向，可以分辨出压力脉冲增长相所引起的前导快波与后随慢波的传播，同时还可观察到压力脉冲恢复相所导致的快模磁声波的传播，由于传播速度的差异，该波动在向外传播的过程中逐渐超过后随慢波。

Evidence suggests that 1 under more stable stratification, the basic flow, if moving faster at low and high levels (particularly in the presence of jets there), allows a resulting meso-β unsteady wave to propagate eastward with respect to basic flow and even at greater velocity compared with it; 2 vertical windspeed shear of basic flow causes instabilities of the TWT perturbation; 3 considering the second derivative of basic-flow wind with respect to z (denoted by zz≠ 0 which is simply given as β* hereafter) the expression for the phase velocity of vortex Rossby wave is obtained, which is unidirectional in propagation with respect to basic flow; 4 VRoW has its physical origin from β*, i.e., from z-varying heterogeneities of y-direction averaged vorticity of the basic flow field; 5 VRoW phase velocity is associated with zonal wave number k, its energy is dispersive and the group velocity exists in the x direction; 6 when windspeed meets the condition of β*, TWT disturbance instability may be that of mixed VRoW and gravity wave; 7 if basic flow is subject to linear shear but does not meet the condition of β*, the TWT instability is that of inertia-gravity wave.

在大气层结比较稳定的情况下，如果基本气流在低层和高层较大(有可能存在低空急流和高空急流)，此时产生的β中尺度不稳定扰动相对于基流向东传播，甚至于快速向东传播。基本气流在垂直方向上的风速切变对于中尺度横波型的扰动起着不稳定的作用。如果考虑基流的二次切变，可以得到涡旋Rossby波的相速度表达式，涡旋Rossby波相对于基本气流是单向传播的。涡旋Rossby波产生的物理根源是基本流场的风速二次切变，亦即基本流场y方向的平均涡度在空间z方向上的不均匀所致。涡旋Rossby波的相速度与纬向波数也有关，它的能量是频散的，其在纬向x方向也存在群速度。在基本流场的风速存在二次切变时，横波型不稳定可能是混合的涡旋Rossby重力波的不稳定；而在基本流场的风速仅仅存在线性切变，不存在二次切变时，横波型扰动的不稳定则是重力惯性波的不稳定。

The results show that when gravity wave's propagating in the homogenous winds, the nonlinearity is stronger in the fair wind than in the contrary wind, the background winds change the propagation velocity and path, and when gravity wave's propagating in the homogenous winds, the vertical wavelength decreases, the average upgoing energy flux reduces which implies the ambient winds absorb the energy of the wave, realizes coupling of the different atmosphere layers.

结果表明，当重力波在均匀风场中传播时，非线性效应在顺风场中比在逆风场中更显著，背景风会改变重力波在水平方向的传播速度和传播路径；当重力波在剪切风场中传播时，重力波在垂直方向上平均能流随高度的增高而减少，表明背景吸收了重力波的能量，在重力波向上传播的过程中，实现了大气各层之间的耦合。

According to the results, we reasonably interpret the physics phenomenons of reflections and progressions by the stress wave.

并依据结果合理地解释了应力波传播过程中反射、叠加等物理现象。

Some regularities of the wave propagation were found from this closed system.

从这个封闭系统中发现了一些瞬态波传播的规律和特点。

In section one, by using FICE scheme and TIME-GCM, a model of trace gases and OH airglow affected by gravity wave is set up, then the propagation of nonlinear gravity wave and the effect on trace gases and OH airglow are analyzed. The result shows gravity wave excited by tropospause forcing can propagate stably to the mesosphere through the stratosphere so that energy and momentum can be transferred from one region to another. In this process, gravity wave undergoes growth, overturning, convection and breaking. And the no-isothermal structure can accelerate the breaking of gravity wave in mesospause, and the breaking of gravity wave is an important source of convection and small-scale waves.

在第一部分的工作中，利用全隐欧拉格式和全球热层-电离层-中间层-电动力学环流耦合模式，对重力波的非线性传播及其在传播过程中对中高层大气中氧族和氢族成分和与之密切相关的OH气辉辐射的影响进行了数值模拟，结果表明，从对流层向上传播的重力波经历了产生、发展、饱和、对流产生直至破碎的非线性演化，大气的非等温结构加速了重力波在中层顶区的破碎，重力波的非线性传播是小尺度对流和湍流产生的一个重要的源。

In section one, by using FICE scheme and TIME-GCM, a model of trace gases and OH airglow affected by gravity wave is set up, then the propagation of nonlinear gravity wave and the effect on trace gases and OH airglow are analyzed. The result shows gravity wave excited by tropospause forcing can propagate stably to the mesosphere through the stratosphere so that energy and momentum can be transferred from one region to another. In this process, gravity wave undergoes growth, overturning, convection and breaking. And the no-isothermal structure can accelerate the breaking of gravity wave in mesospause, and the breaking of gravity wave is an important source of convection and small-scale waves. The propagation of gravity wave will affect the distribution of minor species.

在第一部分的工作中，利用全隐欧拉格式和全球热层-电离层-中间层-电动力学环流耦合模式，对重力波的非线性传播及其在传播过程中对中高层大气中氧族和氢族成分和与之密切相关的OH气辉辐射的影响进行了数值模拟，结果表明，从对流层向上传播的重力波经历了产生、发展、饱和、对流产生直至破碎的非线性演化，大气的非等温结构加速了重力波在中层顶区的破碎，重力波的非线性传播是小尺度对流和湍流产生的一个重要的源。

Lugalbanda was a god and shepherd king of Uruk where he was worshipped for over a thousand years.

Lugalbanda 是神和被崇拜了一千年多 Uruk古埃及喜克索王朝国王。

I am coming just now,' and went on perfuming himself with Hunut, then he came and sat.

我来只是现在，'歼灭战perfuming自己与胡努特，那麼，他来到和SAT 。