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NUMERICAL SIMULATION OF OIL-WATER SEPARATION IN LIQUID-LIQUID HYDROCYCLONES USING A STOCHASTIC TRAJECTORY MODEL

Oil-water separation is frequently encountered in petroleum production engineering. Up to now, this is done mostly by gravity separation technique. Since 80's an important breakthrough has been made in using hydrocyclones for liquid-liquid separation. A geometrical configuration of hydrocyclones, called type F, developed by the researchers from Southampton University, England in 1988 is the most typical ones which consists of double cones and a cylindrical part, and is considered as a standard configuration...

1999, 31(5): 513-520. doi: 10.6052/0459-1879-1999-5-1995-062

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THE APPLICATION OF NUMERICAL SIMULATION IN ANALYSIS OF QIANTANGJIANG TIDE──Ⅰ. NUMERICAL METHOD

The full description of the formation, development and disappear of Qiantangjiangtide by numerical method is presented in this paper in details. In Hangzhou Gulf(near Ganpu),the water region is very wide and the water wave movement are two dimensional, then the two dimensional Saint--Venant equations are used to discribe the movement of waterwave from HangzhouGulf to estuary of Qiantangjiang River (Yanguan). In the Qiantangjiang River (before Yanguan),the water region is narrow and the river is very long, t...

1999, 31(5): 521-533. doi: 10.6052/0459-1879-1999-5-1995-063

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MIXED MODE DUCTILE FRACTURE EXPERIMENT AND ITS CONTROLING PARAMETER

In this paper, the experiment of a series of plain strain mixed mode ductile fractureis carried out in two kinds of ductile materials (quenChed aluminum alloy LY12-CZ and annealedaluminum alloy LY12-M). The microscopic characteristic behavior of deformation and the initiationof blunted crack tip is investigated by using SEM near the area ahead of the blunted crack tip inthe middle thickness profile at the critical range of crack initiation. The adaptability of ductilefracture parameter--void growth ratio is...

1999, 31(5): 534-541. doi: 10.6052/0459-1879-1999-5-1995-064

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THE EFFECT OF THE SECOND SCATTERED WAVE FOR A FINITE CRACK IN AN ELASTIC CAUSED BY DILATATIONAL WAVE

In the dynamic fracture field, the problem with scattered stress wave is very difficultto analyze. At present only a few analytical results have been obtained. Stephen A Than andTsin-Hwei Lu (1970, 1971) treat the transient problem of diffraction of an a plane transient SHwave and an arbitrary plane dilitational wave by a finite crack in an infinite elastic solid. Theyemploy the generalized Wiener-Hopf technique and the standard iteration method. Freund (1990)treat the analogous crack subjected to I load by...

1999, 31(5): 542-549. doi: 10.6052/0459-1879-1999-5-1995-065

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DYNAMIC FRACTURE MECHANICS ANALYSIS FOR NON-HOMOGENEOUS COMPOSITE MAYERIAL WITH MULTIPLE CRACKS

The problem considered here is the response of a nonhomogeneous composite materialcontaining some cracks subjected to dynamic thermal loading. It is assumed that all the materialproperties only depend on the coordinates y (along the thickness direction). In the analysis, theelastic region is divided into a number of strips of infinite length. The material properties are takento be constants for each strip. By utilizing the Laplace transform and Fourier transform technique,the singular integral equations are...

1999, 31(5): 550-562. doi: 10.6052/0459-1879-1999-5-1995-066

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ELASTOPLASTIC BOUNDARY ELEMENT METHOD WITH BIMATERIAL FUNDAMENTAL SOLUTION

The study of problems of bimaterial interface and interface fracture is one of the centralissues of solid mechanics at present. Boundary element method is increasingly manifested to bean effective numerical approach to the study. So an elastoplastic boundary element method withbimaterial fundamental solution, Dundurs-Hetenyi solution, was first proposed by the first authorand is developed in this paper by consideration of the structural features of bimaterial. Becausethe interface conditions of bimaterial a...

1999, 31(5): 563-573. doi: 10.6052/0459-1879-1999-5-1995-067

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TOPOLOGY OPTIMIZATION OF TRUSS STRUCTURES WITH DISCRETE VARIABLES INCLUDING TWO KINDS OF VARIABLES

Because the topology of structure and the sizes of cross sections must be designedin the topology optimization, two kinds of variables, topology variables al and size variables ofcross sections Al are included in the mathematics model of topology optimization. The model isa mixed discrete programming or a pure discrete one including two kinds of variables. It is morecomplex and difficult to be solved than sizing optimization of structures, so it is a challengingproblem in the field of structural optimizatio...

1999, 31(5): 574-584. doi: 10.6052/0459-1879-1999-5-1995-068

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THE MULTI-RITZ-VECTOR METHOD IN GENERALIZED EIGENVALUE PROBLEMS

With reference to the subspace iteration method, the normal Ritz-Vector methodis extended to an improved one i.e. the Multi-Ritz-Vector method in this paper by which theproblem of eigen-value losing for the systems with multi-fold eigen--value in the normal Ritz--Vectormethod can be solved and no eigen-vectors corresponding to multi-fold eigen--value will be lost.Then, it has been pointed out that a singular or ill-conditioned matrix M would lead to anunstable M-orthogonalization procedure of Gram-Schmidt a...

1999, 31(5): 585-595. doi: 10.6052/0459-1879-1999-5-1995-069

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IDENTIFICATION OF LOCAL NONLINEARITIES IN DYNAMIC SYSTEM VIA STOCHASTIC OPTIMAL CONTROL APPROACH

In the analysis of dynamic characteristics of space structures, the connecting elementsplay an important role in the overall dynamics of the structure, which often lead to the structureexhibits local nonlinearities. Generally speaking, the main part of the structure can be regardedas linear with sufficient accuracy, but it is often difficult to model these local nonlinear elementsbecause the complexity of their configuration and operating mode. Therefore, an increasing amountof attention has recently been d...

1999, 31(5): 595-602. doi: 10.6052/0459-1879-1999-5-1995-070

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THE EXPERIMENTAL STUDY OF THE CHAOTIC PHENOMENA OF HEATED JETS

The chaotic phenomena of the coherent structure in the open flow system of heated jetshave been studied by experiments. The present work is concentrated on the relationship betweentypes of the coherent structure in the physical space and asymptotic behaviors of the dynamicalsystem in the phase space.When S = 1 (cold jet), convective instability is everywhere in the flow field. Axisymmetricand belieal modes are the prevailing types of the coherent structure of the jets with two differentnozzle diameters.When...

1999, 31(5): 603-610. doi: 10.6052/0459-1879-1999-5-1995-071

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EFFICIENT BOUNDARY LANER CONTROL ON THICK AIRFOILS USING MULTIPLE SLOTS BLOWING AT SMALL SPEEDS

Boundary layer control on thick airfoils or airfoils at large angle of attack, whichuses very small power input, is studied. The control method is to use multiple slots on the airfoilupper surface tangentially blowing at small speeds. Boundary layer loses its kinetic energy dueto wall friction and adverse pressure gradient gradually along airfoil surface. Therefore, supplyinga small amount of energy at each of the slots located along the airfoil upper surface energizesthe boundary layer and suppresses the s...

1999, 31(5): 611-617. doi: 10.6052/0459-1879-1999-5-1995-072

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POSSIBLE MULTIPLE ROOTS FOR FRACTURE PROBLEMS

In accordance with the relationship between the eigen-matrix rank and sub-eigenfunctiondimension of eigen-values, the maximum number of possible multiple roots for anti-plane problemand in-plane problem is determined. In view of the relationship with eigen-values of anti-plane andin--plane problem, the eigen-values for Reissuer plate consists of two parts. One part associateswith anti-plane problem, the other part pertains to in--plane problem. Therefore, the maximumnumber of multiple roots for anti--plane ...

1999, 31(5): 618-624. doi: 10.6052/0459-1879-1999-5-1995-073

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ON THE BUECKNER WORK CONJUGATE INTEGRAL AND ITS RELATIONS TO THE J-INTEGRAL AND M-INTEGRAL IN PIEZOELECTRIC MATERIALS

This paper deals with crack problems in transversely isotropic piezoelectric material. The formulations of Bueckner work conjugate integrals in these kinds of materials are presented. Furthermore, by introducing two kinds of supplementary "stress-displacement and electricdisplacement-electric field potential" fields, it is proved that are simple but universal relationsbetween the Bueckner work conjugate integral and the J--integral and between the Bueckner workconjugate integral and the M-integral in these ...

1999, 31(5): 625-632. doi: 10.6052/0459-1879-1999-5-1995-074

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TWO-NODE CURVED ELEMENT METHOD FOR GEOMETRICALLY NONLINEAR ANALYSIS OF TENSION STRUCTURES

Various numerical methods including mainly the finite element methods with two--nodestraight-line and polynode curved cable element have been presented to analyze the nonlinearity ofthe tension structures which airs playing a great role in structures. As far as the polynode curvedelement methods are concerned, the precision of which is well but its freedoms are higher, andthe coordinates of inner nodes in the element is usually difficult to determine. The straight-lineelement model leads to bad precision, r...

1999, 31(5): 633-639. doi: 10.6052/0459-1879-1999-5-1995-075

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1999 Vol. 31, No. 5

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