激波

Compared with the initial value problems of scalar conservation laws with smooth flux function, the global weak entropy solutions for the initial-boundary value problems of scalar conservation laws with weak discontinuous flux function include the following new interaction types: a rarefaction wave collides with the boundary and is absorbed compltetely or partially by the boundary; a rarefaction wave collides with the boundary and the boundary will reflect a contact or non-contact shock wave; a contact or non-contact shock wave collides with the boundary and is absorbed by the boundary; a contact or non-contact shock wave collides with the boundary and a new non-contact shock will rebound from the boundary simultaneously or later.

与具有光滑流函数的单个守恒律的初始值问题相比，具有弱间断流函数的单个守恒律初边值问题的整体弱熵解中包括下列新的相互作用类型：稀疏波碰到边界并被边界部分或全部吸收；稀疏波与边界相撞，边界反射出一个接触或非接触激波；接触或非接触激波碰到边界并被边界吸收；接触或非接触激波与边界相撞，边界同时或稍后反射出一个新的非接触激波。

The influences of the shock thickness and Alfven waves on the particle acceleration by diffusive shock waves are numerically studied through solving one-dimensional diffusive equation including the second-order Fermi effect. It is shown that the spectral index of the energetic particles strongly depends on the shock thickness. For example, the spectral index increases from 2.1 to 3.7 in the low energy range of 3-10 MeV and from 2.5 to 5.0 in the high energy range of 20-60 MeV as the thickness increases. The spectral index decreases from 4.3 to 3.1 as the particle injection energy increases. The spectral index decreases from 4.0 to 1.8 at the quasi-steady stage with the enhancement of the compression ratio from 2 to 4. The results indicate that under the influence of Alfven waves, the energetic particle spectrum at lower energy becomes flat and the spectral index decreases from 2.5 to 0.6 in the low energy range of 3-10 MeV and from 11.6 to 5.0 in the high energy range of 20-60 MeV. At the same time, the rollover energy reaches 19.6 MeV. The spectral index decreases from 5.8 to 2.9 as the energy density of Alfven waves increase. All these results are basically consistent with the theoretical models, as well as the observations of typical energetic particle events.

通过数值求解包含二阶费米加速的一维扩散方程，探讨在准平行激波条件下激波厚度和级联阿尔芬波对粒子加速的影响，研究粒子分布函数的演化与激波厚度和阿尔芬波强度的内禀关系，计算结果表明：(1)考虑激波厚度时，谱指数明显依赖于激波厚度，随着厚度从0.32增大到2.56，低能端(3-10MeV)谱指数逐渐从2.1增加到3.7，高能端(20-60MeV)谱指数从2.4增大到5.0，能谱逐渐变软；当初始注入粒子动量增大1.3倍，质子能谱指数从4.3减小到3.1，且与零厚度激波加速的谱指数差值缩小；厚度不变时，随着压缩比从2增加到4，准稳态分布时低能端(3-10MeV)粒子能谱指数逐渐从4.0减小到1.8谱变硬；(2)在级联阿尔芬波的影响下，随着时间的增大，粒子在低能处(3-10MeV)的谱指数从2.5减小到0.6高能端(20-60MeV)谱指数从11.6减小到5.0，能谱变硬，拐点能量值从7.5MeV增大到为19.6MeV；随着波的能量密度增大，谱指数从5.8减小到2.9，这表明阿尔芬波强度越大，加速效率越高，通过与激波厚度解析结果和高能粒子事件的观测能谱比较发现两者是一致的，说明数值模拟结果是可靠的。

Chapter 2 establishes a helicoid model of the 3D curved shock surface, which is a fundamental means for investigating the sweep of the 3D shock surface In chapter 3, the first step is to make definitions and detail concepts about various viewpoints of shock surface sweep. Secondly, those sweep angles of the 3D shock are calculated. After that, with the aid of the helicoid model, two general structure similarity variables are derived which are independent of any model, and their importance in shock structure investigations is discussed.

第三章首先给出激波曲面掠的各种基本概念，计算相应掠角；又借助螺面模型得到一般性的掠相似参数，并分析了它在激波结构研究中的意义，设想了激波气动掠参数的测量方法；第四章依据螺面模型探讨了前缘曲线掠与前缘激波曲面掠的关系，可能存在的均匀激波曲面、简单非均匀激波曲面和它们的运动学设计方法，其中得到一些很有用的概念。

The physical characteristics of various hyperbolic waves in Eular system are analysed. The shock physical characteristics and the conditions of forming the shocklet are discussed, detailedly. We are clear about the mechanism of shocklet excited by continuous waves.The physical mechanism of TS waves and the relation between shocklets and TS waves are studed in a systematic way.

从理论上分析了Eular系统中各种双曲波的物理性质，详细讨论了激波的物理特性和与产生激波的条件，明确了通过连续波动诱发激波物理机理，系统研究了TS波的在可压与不可压流动中的物理特性以及与激波的联系，分析了粘性对激波形成的影响。4。

In the computation of aerodynamic forces, the present work is based on the work of Morino et al., but the following aspects are improved:(1) In computing the steady transonic aerodynamic load, the steady transonic nonlinear integral equation is solved by relaxation-iteration method in this thesis, instead of solving the time dependent transonic nonlinear integral equation, so that the computing time is saved greatly;(2) The influence coeifficients represented by volume integral are transformed to surface integral by using the Gaussian Theorem, so the analytical form of these coeifficients can be obtained and this leads to be more convenient to analyse and compile computer program;(3) The shock capturing method is used in every time step in present work, no shock moving term is added in the integral equation, so that it is more convenient and simpler to treat.

在气动力计算方面，本文基于Morino等人的工作，作了如下几方面的改进：（1）在计算定常跨音速流场（作为非定常绕流计算的初场）时，本文采用松驰迭代法直接求解跨音速定常非线性积分方程，而不是采用时间相关法求解非定常非线性积分方程，这样大大节省了计算机时；（2）将以体积分形式出现的影响系数化为面积分，并获得解析公式，这样便于分析和编写程序；（3）对运动的激波，本文通过在每一个时间步长上采用激波捕捉法而得到，而不是在积分方程中附加激波运动项，因而处理起来简单方便得多。

Numerical results demonstrated that there are three kinds of the instability for the under-expanded supersonic jets according to their shock cell structure patterns:(1) the regular reflection shock cell with a single shear layer,(2) the Mach reflection shock cell with two shear layers and (3) the curved Mach stem with a relatively high expansion ratio.

计算结果表明欠膨胀超声速射流的失稳机制根据射流激波结构的特征可分为3种失稳模式：具有规则反射激波结构和单一剪切层特征的射流不稳定性；带有马赫反射激波结构和双剪切层特征的射流不稳定性；具有弯曲马赫杆和高度欠膨胀射流的不稳定性。

In order to verify the prediction efficiency, 27 interplanetary shock events from January 1979 to June 1982 and 68 interplanetary shock events from February 1997 to January 2000 are used for testing. Comparing the results of our disturbance model to those obtained by STOA and ISPM, we find that our disturbance model is as good as the other two models, and in some cases even better.

为印证扰动传播模型的适用性，利用79年到82年间的27个激波事件，以及97年2月到2000年1月间的68个激波事件，对激波到达地球轨道附近的传播时间进行了预测，并将结果与目前流行的行星际激波事件到达地球轨道时间的STOA和ISPM预报模型所得结果进行了比较。

To obtain a complete picture about shock formation in non-viscous flow, in the succeeding chapter we investigate the isothermal shocks in adiabatic flows. We find that in this case the shock solution still exists, but the structure and the properties of the solution are greatly different from above even qualitatively. In some region of the parameter space there only exists unstable shock solution and in some region of the parameter space there may exist two stable shock solutions.

为得到完整的无粘流体中激波形成的图象，在接下来的第四章，我们研究绝热流体中等温作为激波条件时的情况，发现此时激波解仍存在，但解的结构和性质甚至在定性上都与前两章有了显著的不同：某些参数空间只存在非稳定的激波解，某些参数空间则会同时出现两个稳定的激波解。

The calculated results indicate that a bifurcated A. wave can be formed when the shock passes through the flame, and pre-induced shock transmission in the flame leads to the formation of Mach stem, followed by spheral shock wave. The Rayleigh-Taylor and Kelvin-Helmholtz instabilities occurred in the flame induced by shock wave lead to the flame distortion and breakup.

计算结果表明，激波掠过火团时，分叉形成λ波；前引激波在火团内透射并在轴线处碰撞形成Mach杆，进而逐渐发展为球形激波；火焰在激波作用下先后出现Richtmyer-Meshkov不稳定和Helmholtz不稳定，火焰逐渐变形以致破碎；燃烧速率因此剧增。

The quasi-perpendicular collisionless shock consists of foot, ramp and a series of overshoots and undershoots, after travelling back upstream for a short distance, the reflected protons gyrate back into the downstream where an temperature anisotropy is formed due to an anisotropy of velocity distribution, then excite Alfvén ion cyclotron waves and mirror waves that dissipate the kinetic energy into heat; At quasi-parallel collisionless shocks, the reflected protons can travel far upstream, and lead to the generation of ion beam instabilities which excite large-amplitude right-hand polarized ultralow-frequency resonant waves whose frequencies are are about〓 These waves are convected back downstream by solar wind and gradually merge to form the downstream state, in the meantime new waves are generated continuously in the upstream, this process where ULF waves are generated and merge into downstream state is cyclical.

准垂直无碰撞激波系由根部、斜坡区以及一系列的低冲和过插组成，被激波反射的质子向激波上游运动很短的距离就在回旋作用下再次向下游运动，和激波发生相互作用以后进入激波的下游，在激波的下游引起质子速度分布的各向异性，进而引起激波下游温度的各向异性，激发起Alfvén离子回旋波和镜波，将激波上游的动能耗散成激波下游的热能；在准平行无碰撞激波(θ〓＝10°)情况下，这部分质子能向激波上游运动很大一段距离，并在激波的上游激发起束流不稳定性，引起大振幅的低频波动。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

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如果有任何问题，你可以随时联系我。