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61.
高精度非线性格式WCNS的分析研究与其应用 总被引:1,自引:0,他引:1
首先将Fourier方法推广于高维方向研究了五阶精度WCNS的特性,并与其他高阶格式进行比较。分析结果表明WCNS的高精度特性普遍接近甚至好于迎风偏置五阶显式格式EUW-5与Pade′标准格式。然后开展了WCNS的应用研究,采用高效率的WCNS-E-5数值模拟了含强激波的高维复杂流场。算例包括二维高超声速边界层对自由流扰动波的吸收问题以及三维球头绕流问题。计算结果反映出WCNS-E-5对激波等间断的良好捕捉能力,图像清晰光滑,数据准确可靠。 相似文献
62.
High velocity flows which are exposed to strong rarefaction waves and creating low densities regions in it present difficulties
and inaccuracies for numerical resolution. In particular, variables related to the internal energy are wrongly evaluated.
Use of classical schemes solving the Euler equations in conservative variables introduces significant errors in the determination
of temperature. We recommend to employ a non-conservative formulation of the energy equation. Results found to be more accurate
in using the present internal energy formulation. In order to have the formulation available for both shock and strong rarefaction
waves, we propose a hybrid formulation of conservative and non-conservative ones, depending on a shock indicator. The results
are compared with exact solutions and show a significant improvement of the accuracy. The method is then extended to two-dimensional
cases.
Received 28 March 1997 / Accepted 18 June 1997 相似文献
63.
The interaction of a two-phase flow with a
wedge where a stationary shock wave is initially settled is studied
in a two-dimensional configuration. Before the introduction of
the dispersed phase, the flow around the wedge is a supersonic
one phase flow such as an attached stationary shock wave is
present. Then, the dispersed phase is introduced upstream the
initial position of the stationary shock wave. The purpose of
this study is to point out two-phase and droplets break-up
effects on the oblique shock wave. The two-dimensional
equations are solved by a TVD scheme where fluxes are computed
by using Riemann solver for the gas phase equations and also
for the dispersed phase equations wich is an original approach
due to the authors (Saurel et al. 1994). In addition to drag
forces and heat and mass transfers, the process of droplets
fragmentation based on the particle oscillation is considered.
Accepted April 28, 1995 相似文献
64.
在分析桩土支撑体系及其相互作用关系的基础上,利用有限元分析软件ANSYS建立了群桩
体系计算模型. 通过对均质土体例题计算结果分析,可以看出利用该建模方法与传统解答有
很好的一致性. 根据辽宁工程技术大学实验馆场地土实测资料,利用该建模方法,求解出了承台与桩的
荷载分担比,对安全、经济地进行群桩基础设计具有重要指导作用和应用价值. 相似文献
65.
稀薄流到连续流的气体运动论模型方程算法研究 总被引:10,自引:0,他引:10
通过引入碰撞松弛参数和当地平衡态分布函数对BGK模型方程进行修正,确定含流态控制参数可描述不同流域气体流动特性的气体分子速度分布函数的简化控制方程。发展和应用离散速度坐标法于气体分子速度空间,利用一套在物理空间和时间上连续而速度空间离散的分布函数来代替原分布函数对速度空间的连续依赖性。基于非定常时间分裂数值计算方法和无波动、无自由参数的NND耗散差分格式,建立直接求解气体分子速度分布函数的气体运动论有限差分数值方法。推广应用改进的Gauss-Hermite无穷积分法和华罗庚-王元提出的以单和逼近重积分的黄金分割数论积分方法等,对离散速度空间进行宏观取矩获取物理空间各点的气体流动参数,由此发展一套从稀薄流到连续流各流域统一的气体运动论数值算法。通过对不同Knudsen数下一维激波管问题、二维圆柱绕流和三维球体绕流的初步数值实验表明文中发展的数值算法是可行的。 相似文献
66.
67.
68.
The main difficulty for the numerical calculation of the wave running up a beach is the treatment of its moving water boundary.
In this paper a scheme of turning the free boundary problem into a fixed boundary problem is designed. The calculated run-up
height is consistent with the experiments. Some interesting wave phenomena are also found. 相似文献
69.
Yu. V. Kokhanenko 《International Applied Mechanics》2006,42(7):825-831
The paper studies the three-dimensional stability of an isotropic, linear elastic, rectangular plate under a uniform tensile
load applied to its sides. The concept of free strains is used to reduce the three-dimensional problem to a two-dimensional
one. It is solved using the three-dimensional linearized theory of stability. An approximate solution of the buckling problem
is obtained by the finite-difference method. Numerical results are presented
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 7, pp. 116–123, July 2006. 相似文献
70.
The interaction of a planar shock wave with a loose dusty bulk layer has been investigated both experimentally and numerically.
Experiments were conducted in a shock tube. The incident shock wave velocity and particle diameters were measured with the
use of pressure transducers and a Malvern particle sizer, respectively. The flow fields, induced by shock waves, of both gas
and granular phase were visualized by means of shadowgraphs and pulsed X-ray radiography with trace particles added. In addition,
a two-phase model for granular flow presented by Gidaspow is introduced and is extended to describe such a complex phenomenon.
Based on the kinetic theory, such a two-phase model has the advantage of being able to clarify many physical concepts, like
particulate viscosity, granular conductivity and solid pressure, and deduce the correlative constitutive equations of the
solid phase. The AUSM scheme was employed for the numerical calculation. The flow field behind the shock wave was displayed
numerically and agrees well with our corresponding experimental results.
相似文献