应用数学和力学

2000 Vol. 21, No. 12

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A Numerical Study for Small Amplitude T-S Waves in a Supersonic Boundary Layer

YUAN Xiang-jiang, ZHOU Heng

2000, 21(12): 1211-1214.

Abstract(2513) PDF(583)

Abstract:
The propagation of the disturbance waves in a boundary layer at Mach number=4.5 is studied by direct numerical simulation(DNS),using NND scheme,and different amplitudes A=0.01,0.001,0.000 1 of the disturbance have been assumed.The numerical result shows that there might be shocklets induced in the b...

Theoretical Study on the Bifurcation of Vortexes Structure for Flow in Curved Tube

WU Wang-yi, TAN Wen-chang, LI Juan, XIE Wen-jun

2000, 21(12): 1215-1226.

Abstract(2859) PDF(801)

Abstract:
The number and distribution of the singular points of streamlines in the cross section of steady flow through a curved tube are discussed by using the method of topological structure analysis. And a theoretical criterion is obtained for the bifurcation of flow vortexes for the secondary flow turning...

Superposition About the 3D Vortex Solutions of the Fluid Dynamic Equation

HUANG Yong-nian, HU Xin

2000, 21(12): 1227-1237.

Abstract(2657) PDF(788)

Abstract:
A class of exact general solutions of an axisymmetric flow of the fluid dynamic equations is given.Then some examples are discussed.Some vortex solutions can be superposed to give other exact solutions.It can be used to analyse the generation and evolution of the vortex ring.

Numerical Simulation of Standing Solitons and Their Interaction

ZHOU Xian-chu, Rui Yi

2000, 21(12): 1238-1246.

Abstract(2604) PDF(554)

Abstract:
Standing soliton was studied by numerical simulation of its governing equation,a cubic Schr^Ldiger equation with a complex conjugate term,which was derived by Miles and was accepted. The value of linear damping in Miles equation was studied.Calculations showed that linear damping effects strongly on ...

Penalty Finite Element Method for Nonlinear Dynamic Response of Viscous Fluid-Saturated Biphasic Porous Media

YAN Bo, ZHANG Ru-qing

2000, 21(12): 1247-1254.

Abstract(2905) PDF(751)

Abstract:
The governing equations as well as boundary and initial conditions for nonlinear dynamic response problems of viscous fluid-saturated biphasic porous medium model,based on mixture theory,are presented.With Galerkin weighted residual method the corresponding nonlinear dynamic penalty finite element e...

Research on Stability of Moving Jet Containing Dense Suspended Solid Particles

LIN Jian-zhong, ZHOU Ze-xuan

2000, 21(12): 1255-1264.

Abstract(2414) PDF(481)

Abstract:
The spatial stability equation of moving jet containing dense suspended solid particles was derived out by means of the continuum phase-coupled model.The stability curves of moving jet for different downstream distances,Reynolds number of flow-field,particle properties and velocities of jetting devi...

The Variational Principles and Application of Nonlinear Numerical Manifold Method

LUO Shao-ming, ZHANG Xiang-wei, CAI Yong-chang

2000, 21(12): 1265-1270.

Abstract(2312) PDF(577)

Abstract:
The physical-cover-oriented variational principle of nonlinear numerical manifold method (NNMM)for the analysis of plastical problems is put forward according to the displacement model and the characters of numerical manifold method(NMM).The theoretical calculating formulations and the controlling e...

Variational Method and Computation for H_∞ Control

ZHONG Wan-xie

2000, 21(12): 1271-1278.

Abstract(2345) PDF(674)

Abstract:
The variational approach is further applied to the measurement feedback H_∞ control problems.Based on the induced norm description of the system Г,the variational functionals J_c and J_p of state feedback H_∞ control for the future time interval(t,t_f],and of H_∞ filter for the past time interval[0,t),res...

Precise Integration Method for LQG Optimal Measurement Feedback Control Problem

ZHONG Wan-xie, CAI Zhi-qin

2000, 21(12): 1279-1284.

Abstract(2538) PDF(909)

Abstract:
By using the precise integration method,the numerical solution of linear quadratic Gaussian(LQG)optimal control problem was discussed.Based on the separation principle,the LQG control problem decomposes,or separates,into an optimal state-feedback control problem and an optimal state estimation probl...

Two Types of New Algorithms for Finding Explicit Analytical Solutions of Nonlinear Differential Equations

ZHANG Hong-qing, YAN Zhen-ya

2000, 21(12): 1285-1292.

Abstract(2649) PDF(925)

Abstract:
The idea of AC=BD was applied to solve the nonlinear differential equations.Suppose that Au=0 is a given equation to be solved and Dv=0 is an equation to be easily solved.If the transformation u=Cv is obtained so that v satisfies Dv=0,then the solutions for Au=0 can be found.In order to illustrate t...

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CHEN Da-duan, SHI Wei-hui

2000, 21(12): 1293-1300.

Abstract(2371) PDF(561)

Abstract:
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The C^k Instability of Navier-Stokes Equation Appending Polynomials of Unknown Functions

HE You-hua, SHI Wei-hui

2000, 21(12): 1301-1309.

Abstract(2388) PDF(673)

Abstract:
Applying the theory of stratification,the solution space structure about a class of deformed Navier-Stokes equation is determined.It is proved that such kind of equation has no C^k(k≥2)stable solution by the fact that the strate transversale is a null set.

On the Partially Cavitating Flow Around Two-Dimensional Hydrofoils

CHENG Xiao-jun, LU Chuan-jing

2000, 21(12): 1310-1318.

Abstract(2927) PDF(615)

Abstract:
The steady partially cavitating flow around two-dimensional hydrofoils was simulated numerically by the low-order potential-based boundary integration method.The caviy shape and length are determined for given cavitating numbers in the course of iteration by satisfying the kinematic and dynamic boun...