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Physical and Numerical Aspects of Self-Induced Shock Oscillatory Flowfields.

自激激振荡流场的物理和数值方面。

基本信息

批准号：
11650173
负责人：
MATSUNO Kenichi
金额：
$ 1.34万
依托单位：
Kyoto Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650173/
关键词：
Shock wave Self-induced oscillation Compressible flow Supersonic flow Jet Numerical analysis CFD Spectral analysis

项目摘要

Self-Induced shock oscillation is essential physics in flow filed of supersonic under-expanded jet. Although there are many simulations for the self-induced shock oscillation flow fields, there exist strong dependency of resultant frequency on schemes used. Thus each schemecalculates its frequency of the oscillation. Thus, it is verydifficult to simulate these flow fields since the real physics should reveal only type of spectrum. The purpose of the present project is to investigate the cause of this difference and to develop the accurate and suitable scheme to calculate such self-induced shock oscillation.The project has been carried out during fiscal years 1999 to 2001. In the project, four types of the flow fields have been investigated with three types of flux functions and explicit/implicit time integration schemes. Parametric studies on the effect of the grid spacing and time/space accuracy. Results show the following conclusions. Viscous effect is not strong, the inviscid transportation of the vortices is essential physics of the shock oscillation. As for the effect of the grid spacing, the large grid spacing produces large numerical damping and results non-oscillatory flow. Thus it is shown that the appropriate resolution is essential for capturing shock oscillations. Although geometry of the problem is axisymetric, threedimensional effect is shown to be important. In this project, a new numerical scheme which especially suitable to simulate unsteady shocked flows has been proposed and developed. The scheme is based and estimated on the space-time control volume in order to assure the conservation of the physical properties and geometric properties.

自激激波振荡是超声速欠膨胀射流流场的基本物理现象。虽然有许多模拟的自激激波振荡流场，有很强的依赖性，所使用的格式的合成频率。因此，每一个schemecalculates它的振荡频率。因此，由于真实的物理学只能揭示光谱的类型，因此很难模拟这些流场。本项目的目的是调查这种差异的原因，并制定准确且合适的方案来计算这种自激冲击振荡。该项目已于1999至2001财政年度进行。在本计画中，我们使用三种流量函数及显式/隐式时间积分格式，研究了四种流场。网格间距和时间/空间精度的影响的参数研究。结果显示以下结论。粘性效应不强，旋涡的无粘输运是激波振荡的基本物理过程。对于网格间距的影响，大的网格间距产生大的数值阻尼，导致非振荡流动。因此，它表明，适当的分辨率是必不可少的捕捉冲击振荡。虽然问题的几何形状是轴对称的，但三维效应是很重要的。在本计画中，我们提出并发展了一种特别适合于模拟非定常冲击流的数值格式。该方案是基于时空控制体的估计，以保证物理性质和几何性质的守恒。