力学学报

EXTENSION AND EXAMINATION OF KOBUS THEORY FOR THREE-DIMENSIONAL BUBBLE PLUME

The Kobus theory for 3-D bubble plume is examined in terms of some typical experimental data. The formulas for calculating all empirical constants in the Kobus theory are presented, so that Kobus theory can be used more conveniently in practical applications. The Kobus theory is evaluated as well.

1990, 22(6): 641-651. doi: 10.6052/0459-1879-1990-6-1995-995

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THE CHARACTERISTICS OF LAMINAR SIDEWALL BOUNDARY-LAYER FLOWS IN A DUSTY-GAS SHOCK TUBE

Laminar sidewall boundary-flayer flows in a dusty-gas shock tube are solved numerically by a finite-difference procedure. The results indicate that there exist three different characteristic flow regions. The details are given of an implicit four-and six-point scheme to study the development of the boundary layer. An appropriate non-Stokes relation to describe the interaction between the two phases is employed. The resulting velocity and temperature profiles across the boundary layer are given for gas and p...

1990, 22(6): 652-659. doi: 10.6052/0459-1879-1990-6-1995-996

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THE SPEED OF SOUND IN TWO-PHASE FLOWS UNDER THE CONDITION OF VELOCITY-EQUILIBRIUM BETWEEN PHASES

Under the condition of velocity-equilibrium between phases, a general expression for the speed of sound in two-phase flows without phase change has been obtained. After introducing an adiabatic or thermo-equilibrium assumption between phases, the expression reduces to a particular expression for the complete or partial equilibrium speed of sound. Various expressions for the velocity-equilibrium speed of sound in two-phase flows published in literature can be derived from the general expression as special ex...

1990, 22(6): 660-669. doi: 10.6052/0459-1879-1990-6-1995-997

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THE MODULATIONAL THEORY OF NONLINEAR GRAVITY-WAVE IN FLUID WITH VARYING DEPTH AND NONUNIFORM CURRENT

Using the method of multiple scales and WKB expansion a new fourth order evolution equation of amplitude of Stokes wave train in two-dimensional fluid with slowly varying depth and current has been derived. Effects of varying depth and current OB the-evolution of a single envelope have been calculated by the finite-difference method.

1990, 22(6): 670-679. doi: 10.6052/0459-1879-1990-6-1995-998

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A 3-D COMPOSITE CONSTITUTIVE MODEL OF ELASTO-PLASTICiTY FOR POLYCRYSTALLINE MATERIALS

This paper is aimed at developing an elasto-plastic constitutive model for polyc-rystalline materials. The model is an energy-equivalent system composed of extensivecompressive components well-oriented and distributed uniformly in the 3-D space to simulate how the mic-rostructures of materials store and dissipate energy during deformation and slippage. The components are extended/compressed compatibly with the overall strain and each of them undergoes its own elongation history dependent on its orientation....

1990, 22(6): 680-688. doi: 10.6052/0459-1879-1990-6-1995-999

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COMPLEX VARIABLE ANALYTIC METHOD FOR SOLVING REISSNERS PLATE BENDING PROBLEMS

In this paper, a general complex variable analytic method for solving the bending problems of Reissner's plate is proposed. Some interested problems, such as stress concentration problems of Reissner's plates with holes, can be solved effectively by means of this method. As applications, the bendings of Reissner's plates with circular and elliptic holes are discussed respectively.

1990, 22(6): 689-699. doi: 10.6052/0459-1879-1990-6-1995-1000

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SCATTERING OF ELASTIC WAVES BY MULTIPLE NON-COP-LANE INTERFACE GRIFFITH CRACKS IN A LAYERED MEDIUM

In this paper an analysis of scattering of elastic waves by multiple non-coplane interface Griffith cracks in a layered medium is presented. Making use of Fourier integral (transform, the problem is reduced to a set of dual integral equations which can be reduced further to a set of singular integral equations and then solved by numerical methods. As an example, the scattering of SH waves by two cracks in two layered half-space has been investigated in more detail. The features of the scattering waves at th...

1990, 22(6): 700-716. doi: 10.6052/0459-1879-1990-6-1995-1001

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ELASTIC-PLASTIC ANALYSIS OF CENTRAL SHORT CRACKS

Fully plastic solutions of J integral and Crack Opening Displacement for panels with a central short crack under the action of a uniform load are obtained by the modified energy method. The corresponding elastic-plastic solutions are also obtained by the-engineering method of elastic-plastic analysis. The comparison of the obtained results with those of infinite bodies shows that the difference is within 5% when a/b<0.05. On the other hand, in the case that a/b>05, the error may not be negligible if the sol...

1990, 22(6): 717-724. doi: 10.6052/0459-1879-1990-6-1995-1002

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A STUDY ON ELECTRONIC SHEARING SPECKLE TECHNIQUE

In this paper, a new method of deformation measurement is described. By means of the laser shearing speckle interference as the mask of deformation information and with video, electronic signal processing technique combined with the micro-computer, the electronic interferometry is realized. The visibility of the strain fringe pattern produced by the electronic interference from deformation information is demonstrated. The electronic interferometry hardware and software are studied and designed. The basic sy...

1990, 22(6): 725-731. doi: 10.6052/0459-1879-1990-6-1995-1003

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DIAGONAL IMPLICIT ALGORITHM FOR THE EULER EQUATIONS IN THE TRANSONIC CASOADE FLOW FIELD

Based on the unfactored implicit flux-splitting finite area algorithm, a diagonal form one-way implicit algorithm for the Euler Equations is presented and an accurate implicit numerical treatment for boundary conditions on the wall is given in this paper. The numerical results have shown that this algorithm is efficient.

1990, 22(6): 732-736. doi: 10.6052/0459-1879-1990-6-1995-1004

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EXPERIMENTAL STUDIES ON SHOCK WAVE STRUCTURES IN THE IMPINGEMENT OF THE REAL ROCKET JET

In this paper, the pictures of shock wave structures in the flow field of real rocket jet impingement were gotten by a very effective Laser-Moire interference system. So the problem of taking the picture of real rocket jet with high temperature, high velocity and strong flame was solved. Using this system, we studied jet impinging cone and found some new shock wave structures.

1990, 22(6): 737-741. doi: 10.6052/0459-1879-1990-6-1995-1005

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STABILITY OF A FLOW WITH SHOCK WAVE

The problem of stability of shock waves from thermodynamic piont of view is treated in this paper. Xu Fu discussed stability of shock waves in the sense of Landau and Lifshitz. In this paper we regard flow as a thormodynamic nonequlibrium system. On the basis of some principle of nonequlibrium thermodynamics we treat the problem of thermodynamic stability of shock waves. The conclusions obtained are: the weak shock (including sound waves) is critically stable, the normal plane shock is unstable.

1990, 22(6): 742-747. doi: 10.6052/0459-1879-1990-6-1995-1006

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ON THE PROBLEM OF NONLINEAR REISSNER PLATE

Some types of variationai principle and bound d.eorem are obtained. An approximate theory, which uses the stress function and two displacement functions as its variables, is established

1990, 22(6): 748-752. doi: 10.6052/0459-1879-1990-6-1995-1007

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THE ENERGY METHOD OF MULTIPLE RESONANCE IN NONLINEAR VIBRATION OF ELASTIC BODY

Based on the averaging method in the non-linear vibration theory and combined, with the mechanical energy conception, the energy method for the problem of multiple resonance in non-linear vibration of elastic shaft system has been found. Using this method we have researched, among others, the two fold resonance on rotor shaft system of generator. Its proved that the energy method is applicable and simple. Some new phenomena of two fold re-sonance are revealed. The theory is verified by experiment.

1990, 22(6): 753-758. doi: 10.6052/0459-1879-1990-6-1995-1008

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1990, 22(6): 759-762. doi: 10.6052/0459-1879-1990-6-1995-1009

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1990 Vol. 22, No. 6

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