力学学报

WEAKN ON-LINEAR INTERACTION BETWEEN SOUND&VORIEX IN SHEAR FLOW AND MECHANISM OF FLOW CONTROL BY SOUND

The identification of sound and vortex and their interaction in nonuniform flow are discussed using split technique of velocity vector and asymptotic expansions.In particular,second order interaction in shear flow is considered.The result is used to explain the phenomena in airfoil flow controled by sound.After calculating the amplification of second order vortex,the effective vortex patterns and the relation between vortex frequency and sound frequency are obtained.In addition,the threshold value of sound ...

1995, 27(S): 1-7. doi: 10.6052/0459-1879-1995-S-1995-496

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THE RECONSTRUCTION OF 3D TEMPERAIURE DISTRIBUTION IN HEAT FLOW BY SAMPLING THEOREM

Based on the fact that only few fringes can be obtained in the low temperaturegas flow,the sampling theorem is adopted for reconstructing the 3D temperature distri-bution. The computer simulation results are given with this algothm. A test flow field is reported.The fringes of heat flow are processed and measured by computer automaticprocessing system. Temperature distributions on two cross-sections of the heat flow are displayed.

1995, 27(S): 8-13. doi: 10.6052/0459-1879-1995-S-1995-497

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NUMERICAL SOLUTION OF THE FLOW OF A BINGHAM FLUID ON A ROTATING DlSK

The equation describing the flow of a Bingham fluid on a rotating disk are derivedand the equation of the film thickness distribution is solved numerically using the differencemethod.Two kinds of thickness distribution have been found.The numerical solutionsagree with the experimental result of the magnetic disk used in electronic computers andthe result of Jemekhe and Schuldt respectively.

1995, 27(S): 14-19. doi: 10.6052/0459-1879-1995-S-1995-498

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NUMERICAL SIMULAION OF AGITATED FIBRE-SUSPENSION FLOWS

, Yurun Fan

Because there are no suitable constitutive equations available to describe me-chanical behaviour of fibre suspensions in viscoelastic fluids,research efforts have been so ferlimited to fiber suspensions in Newtonion fluid. The constitutive equation for fibre suspen-sions in the Oldroyd-B fluid is improved by adopting the NUCM model, and 2-D agitatedfibre suspension flows both in the Newtonian and Oldroyd-B fluid are simulated numeri-cally. The results indicate that the model and the numerical method used in...

1995, 27(S): 20-29. doi: 10.6052/0459-1879-1995-S-1995-499

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混流式转轮内有旋流动的全三元反问题计算

An inverse method of a full three dimensional rotational flow for the design ofmixed flow runner is described.The mean flow equations are derived from the 3-D Eulerequations by use of circumferential averaging method and the periodic flow equations areobtained from Clebsch formulation. The blades are represented by superposition of vorticesand sources. The distribution of V_(θr)and thickness is prescribed and the corresponding bladeShape is computed iteratively. The method is applied to the design of mediul...

1995, 27(S): 30-36. doi: 10.6052/0459-1879-1995-S-1995-500

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WEAKENING OF AN ELASTIC PLAIE BY A DOUBLLY-PERIODIC ARRAY OF CRACKS

The interaction of cracks in a doubly periodic arrey with one collinear directionis analysed and a new approximate method of solving the problem is developed based onthe segragation analysis and superposition principle. The stress intensity factors of cracktips and the displacement jump across the crack surface are expressed by analytic or semi-analytic form. The effective moduli and the compliance matrix of the cracked plate are alsoformulated.The method is effective with its simple procedure and high accu...

1995, 27(S): 37-50. doi: 10.6052/0459-1879-1995-S-1995-501

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COMPARISON OF FINITE ELEMENT CALCULAION AND EXPERIMENTAL STUDY OF ELASTIC-PLASTIC DEFORMATION AT CRACK TIP

The strain field around a mode Ⅰ crack tip with plane stress deformation forFe-0.5%Si material specimen was measured by SEM,micro grid method and digital imageprocessing. Finite element method(FEM) for elastic-plastic deformation was used to cal-culate the experimental object. Comparison of experimental and FEM results showed thatFEM based on the updated Lagrangian formulation was in good accordance with experi-mental measurement.But some factors,e.g.,plastic dilatancy,should be included as cracktip was nea...

1995, 27(S): 51-57. doi: 10.6052/0459-1879-1995-S-1995-502

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NUMERICAL ANALYSIS FOR DETECTION OF DELAMINAION IN LAMINATES BY PIEZOELECTRIC SENSORS

A composite laminate with bonded piezoelectric film as sensor under uniaxilstretching is analyzed by means of modified quasi threed-dimensional finite element method.The influence of piezoelectric layer on interlaminar stresses is discussed and then the voltagedistribution on piezoelectric sensor is obtained in the presence of delamination. The resultsshow that it is feasible to detect the delamination by use of piezoelectric sensor. Finally,various affecting factors are discussed.

1995, 27(S): 58-65. doi: 10.6052/0459-1879-1995-S-1995-503

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STRESS ANALYSIS OF FINITE COMPOSITE LAMINATES WITH MULIIPLE ELLIPTICAL HOLES

Based on the classical laminated plate theory, a finite composite laminated plateweakened by multiple elliptical holes is treated as an anisotropic multiply connected plate.Using the complex potential method in the theory of elasticity of an analytical solution offinite composite laminates containing multiple elliptical holes is obtained with the help ofthe Faber series expansion and the least square boundary collocation technique. The effectsof many design parameters on the stress distribution are studied ...

1995, 27(S): 66-73. doi: 10.6052/0459-1879-1995-S-1995-504

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THE APPLICATION OF KANTOROVICH METHOD AND METHOD OF LINES TO HIGH GRADIENT PROBLEMS

In this paper,the two semi-analytic numerical methods,i.e. Kantorovich methodand MOL,are applied to the high gradient problems in [1]. The obtained numerical resultsare satisfactory. In particular,we have tried the combination of the multi-sub-structuremethod and MOL. As a result,the precision of the numerical results and the efficiency ofthe solution are improved greatly. Therefore, the results of this feasibility study provide anew promising approach to tackle the high gradient deformation in“the shear ba...

1995, 27(S): 74-80. doi: 10.6052/0459-1879-1995-S-1995-505

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INTEGRATING FACTORS AND CONSERVATION LAWS FOR NONHOLONOMIC NONCONSERVATIVE DYNAMICAL SYSTEMS

通过寻找积分因子来建立非完整非保守系统的守恒律，讨论了存在守恒定律的必要条件，并举例说明其应用。

1995, 27(S): 81-87. doi: 10.6052/0459-1879-1995-S-1995-506

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ON STABILITY OF UPRIGHT STANDING HUMAN BODY

The stability problem of an upright standing human body is discussed in this paper. A controlled reverse double-Pendulum is considered as the model.The subjective and objective conditions of stability are analysed, and the dynamic stable domain,which restricts the projection of body' s center of gravity on the ground is given to explain the phenomena in practice theoretically.

1995, 27(S): 88-91. doi: 10.6052/0459-1879-1995-S-1995-507

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EXPERIMENTAL INVESTIGATION OF TRANSFORMAION ZONE IN CERIA-STABILIZED TETRAGONAL ZIRCONIA POLYCRYSTAL

Transformation zone in a single-edge notch bending specimen of ceria-stabilizedtetragonal zirconia polycrystal was studied by moire interferometry.The transformationzone with a characteristic elongated shape ahead of the notch was observed and the distri-bution of plastic strain within the transformation zone was obtained from the moire fringepatterns. This work provides a significant experimental foundation for establishing the the-oretical models of transformation toughening.

1995, 27(S): 92-97. doi: 10.6052/0459-1879-1995-S-1995-508

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MACH NUMBER EFFECTS ON SEPARATION BEHAVIORS INDUCED BY SWEPT SHOCK WAVE

An experimental investigation was made for the shock wave/turbulent boundary-layer interactions induced by swept compression corners.The techniques used in this studywere the surface pressure distribution measurement and surface oil-film streak visualization.Effects of upstream Mach number M_∞ on the behavior of separation and the condition forincipient separation were mainly studied. The test Mach numbers were 1.79,2.04 and 2.50and the Reynolds numbers were about 2.42 2.47×10￣7/m。 15 compression corner mo...

1995, 27(S): 98-102. doi: 10.6052/0459-1879-1995-S-1995-509

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THE TESTING RESEARCH FOR OPTIMIZING THE DESIGN OF TRANSONIC ADAPTIVE TEST SECTION

This paper discusses the wall interference distribution of testing 3-D models in rectangular test section and the suitable width/height ratio B/H of the test section for extending wall interference free area.Two wing-body models were tested in Northwestern Polytechnical University(NPU)2-D flexible wall adaptive wind tunnel with B/H=1.0,1.2 and 1.4.The two models were tested in Germany DLR high speed wind tunnel HKG too. The results shows that for testing aircraft models B/H=1.4 is suitable.

1995, 27(S): 103-108. doi: 10.6052/0459-1879-1995-S-1995-510

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MEASUREMENTS OF VISCOSITY OF A LATTICE GAS USING A PROBABILITY MODEL

A probability type lattice gas model is proposed,using Boltzmann approxi-mation. Kinamatic shear viscosity of the lattice gas is mesured by numerical simulation ofPoiseuille flow.Quantitative comparison of the numerical results with theoritical ones areshown, they are in good agreement.

1995, 27(S): 109-113. doi: 10.6052/0459-1879-1995-S-1995-511

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THE INVESTIGAION OF ASYMMETRIC SEPARAION ON SLENDER BODY

Vortex structure on the slender bodies at supsonic flow is investigated by numer-ical method.The Navier-Stokes equations and TVD scheme are applied for the numerical simulation.The results present some characteristics of flow over the slender cone,hemi-spheric cylinder and elliptic cone and show that within the range of angle 1 5° 25°,the asymmetric vortices are formed on the leeside of slender cone and no asymmetric vortices are found for the hemisphere cylinder or elliptic cone at angle of attack of 32.5...

1995, 27(S): 114-119. doi: 10.6052/0459-1879-1995-S-1995-512

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A MICRO-MODEL OF DUCTILE FRACTUKE AND IT’S APPLICAION TO CONSTRAINED FRACTURE

The damage evaluation near a crack tip in different fracture specimens andsmall scale yielding model are analyzed in detail.It is proposed that the initiation of ductilefracture is equivalent to saying that the damage at a characteristic position ahead of thecrack reaches a critical value. Using this model the macroscopic fracture toughness, inagreement with experimental data and with theoretical fracture toughness independent ofconstraint are obtained.

1995, 27(S): 120-124. doi: 10.6052/0459-1879-1995-S-1995-513

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APPLICAION OF METHOD OF COMPLEX FUNCTION TO DYNAMIC STRESS CONCENTRAIONS IN THIN PLATE WITH CUTOUTS

Complex varible analytic method for soving dynamic stress concentration in thin plate with cutouts is proposed. Numerical results for stress concentration of a plate with circular and elliptic holes are presented.

1995, 27(S): 125-134. doi: 10.6052/0459-1879-1995-S-1995-514

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THE NON-CONFORMING DISPLACEMENT FUNCTIONS OF REFINED DIRECT STIFFNESS METHOD AND THEIR CONVERGENCE

The non-conforming displacement functions of refined direct stiffness methodare presented. With the application of IPT test, a new convergence test, which is calledstrong-IPT test, for separable(C￣0)non-conforming element is established. The test is asufficient one for the convergence and particularly it is valid for the(C￣0)refined element. Inaddition,a class of(C￣0)refined element are proposed and they are proven to pass strong-IPTtest.

1995, 27(S): 135-142. doi: 10.6052/0459-1879-1995-S-1995-515

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