EI、Scopus 收录
中文核心期刊
Quick Search Issue Search Advanced Search

1998 Vol. 30, No. 1

  Previous Issue | Next Issue 
Display Method:
THE DIRECT NUMERICAL SIMULATION OF THREE DIMENSIONAL MERGER FOR TWO PARALLEL VORTEX TUBES
By direct numerical simulation of Navier-Stokes Equations, we investigate the three-dimensional merger of two perturbed parallel vortex tubes in this paper. The pseudo-spectral method is used. It is found that the three dimensional merger takes place in the manner of twinning similar to helical pairing. It is worthy of special mention that the concentration of vorticity occurs in non-axial x and y directitions its maximum value can reach even more than 30 percent of the initial peak vorticity and it...
1998, 30(1): 1-8. doi: 10.6052/0459-1879-1998-1-1995-091
PDF
NUMERICAL SOLUTION OF BACKWARD-STEP SEPARATION FLOW IN OPEN CHANNEL 1)
By use of the large-eddy simulation, numerical solutions of two-dimensional backward-step separation flows in open channels are obtained. The behavior in different regions for step-induced separation flow and statistical characteristics for fluctuation pressure on the wall within the reattachment zone is investigated. The results obtained are compared with the experimental values. A weakly compressible flow model and a non-uniform grid are used in this paper. The calculated results show that the method of t...
1998, 30(1): 9-19. doi: 10.6052/0459-1879-1998-1-1995-092
PDF
MULTISPECIES LATTICE-BOLTZMANN MODELS FOR MASS DIFFUSION 1)
A multispecies, multispeed lattice Boltzmann model is presented to study the mass diffusion properties. We introduce the particles with different speed and different species. The particles of same species have same mass and speed. At each node the total momentum of all particles and the partial masses of the particles of same species are conserved. Using the Chapman-Enskog method, we have derived from the BGK Boltzmann equation the macroscopique conservation equations that yield the N-S equation and partial...
1998, 30(1): 20-26. doi: 10.6052/0459-1879-1998-1-1995-093
PDF
LOCAL WAVE FORCES ON A VERTICAL CIRCULAR CYLINDER INDUCED BY REGULAR WAVES 1)
The local wave forces acting on vertical circular cylinder in regular waves have been investigated experimentally under the condition that the K C number were in the range 4 0 to 35 and the Reynolds numbers 6× 10 3 to 2× 10 4 . Based on Morison equation and the second-order Stokes wave theory, the local drag, inertia and the maximum lift coefficients: C D, C M and C L max along the cylinder are computed. It hase been found that the C D, C M and C L max values very ...
1998, 30(1): 27-34. doi: 10.6052/0459-1879-1998-1-1995-094
PDF
COMPUTATIONAL AND EXPERIMENTAL INVESTIGATION ON THE 3-D FLOW FEATURE AND ENERGY DISSIPATION CHARACTERISTICS OF PLUNGE POOLS 1)
Investigating the flow field of plunge pool is the bas is of studing the energy dissipation problem in plunge pool. However, the flow features in plunge pool have not been understood fully up to now. Not only little has been obtained for the numerical simulation (especially the 3-D numerical simulation), but the 3-D flow field has not been measured in physical model. In fact, it is the combination of numerical and experimental methods that is effective in the research of such complicated flow as in plunge p...
1998, 30(1): 35-42. doi: 10.6052/0459-1879-1998-1-1995-095
PDF
A NONLINEAR MODEL OF SURF BEAT 1)
A nonlinear, short-wave-averaged model of surf beat, which describes essentially long-period motions associated with the mean free surface,is presented. The numerical techniques used in the solution are based on so-called Weighted-Average Flux (WAF) method, with Time-Operator-Splitting (TOS) used for the treatment of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modelling breaking long waves. The short wave (or primary-wave) energy e...
1998, 30(1): 43-50. doi: 10.6052/0459-1879-1998-1-1995-096
PDF
A NEW METHOD OF IDENTIFYING THE TYPES OF MOTION OF A NONLINEAR CRACKED ROTOR 1)
A cracked rotor is a complicated nonlinear time-varying dynamical system and its types of motion can be periodic, quasiperiodic or chaotic when the parameters of system changes. For a given set of parameters of the system, Poincare section,power spectrum, wave form and Lyapunov exponent are usually utilized to see whether the response of the system is chaotic or not, but it is difficult to determine precisely the domains or attracting basins of different types of motions in parametric space or initial value...
1998, 30(1): 51-57. doi: 10.6052/0459-1879-1998-1-1995-097
PDF
EFFECT OF CHANGING TEMPERATURE ON ACTIVE CONTROL OF VIBRATING FREQUENCY OF PIEZOELECTRIC CIRCULAR PLATES 1)
This paper is to quantitatively study the characteristics of active control of vibrating frequency of a piezothermoelectric circular plate with nonlinear deformation, and the effect of changing temperature of environment and the large amplitude of vibration on the characteristics.The results show that the changing temperature of environment of the plate has influence on the controlled frequency of vibration of the plate by means of piezoelectric voltage. When the controlled voltage is high enough, the effec...
1998, 30(1): 58-64. doi: 10.6052/0459-1879-1998-1-1995-098
PDF
DYNAMICAL ANALYSIS ON THE FORMATION OF DISLOCATION PATTERN IN THE EASY SLIP STAGE OF SINGLE CRYSTALS 1
The mechanism governing the conservative climb of dipoles and a new dislocation dynamic model for single slip are proposed. Using this model, the formation of the carpet that is a planar array structure in the I stage of crystal hardening is predicted, in agreement with the experimental results. The present model takes into account not only the drift and climb mechanism of dipoles but also the three-dimensional movement of plus and mines mobile dislocations through slipping and cross-slipping. Besides, the ...
1998, 30(1): 65-75. doi: 10.6052/0459-1879-1998-1-1995-099
PDF
BIFURCATION, BULGING AND WRINKLING OF A SQUARE SHEET METAL WITH NON-UNIFORM TENSION 1)
The bifurcation, bulging and wrinkling behaviors of square sheet metals with non-uniform tension (called as YBT) are numerically simulated, based on Hill's sufficient condition ofυniqueness for elastic plastic materials, virtual power-rate variational principle, and Mindlin shell element model The calculated results are compared with experimental ones Finally, the effects of the sheet thickness t and the tensile width B at the boundary surface of bifurcation and wrinkling models are discussed ...
1998, 30(1): 76-82. doi: 10.6052/0459-1879-1998-1-1995-100
PDF
BIFURCATION STUDY OF SHALLOW ARCH UNDER PERIODIC FORCE 1)
The complicated dynamics of shallow arch with periodic excitation for the case of 1:2 internal resonance is studied in this paper.It is pointed out that when the arch has an initial deflection,the first order and the second order modes can be in resonance and react to each other;therefore the energy can be transimitted between the low and high modes.The Hopf bifurcation solution after symmetric breaking can lead to chaos by a sequence of period-doubling bifurcations. The steady state periodic solutions can ...
1998, 30(1): 83-88. doi: 10.6052/0459-1879-1998-1-1995-101
PDF
FUNDAMENTAL SOLUTIONS OF SYMMETRICAL LAMINATED THICK PLATES ON ELASTIC FOUNDATION 1)
In this paper the governing partial differential equations of symmetrically laminated thick plates including transverse shear deformation are transferred into ordindary differential equations by the use of the method of a plane wave decomposition. Then the ordinary differential equations are transferred into a sixth-order ordinary differential equation. Fundamental solutions of symmentrically laminated thick plates including transverse shear deformation on elastic foundation are presented in the form of a d...
1998, 30(1): 89-95. doi: 10.6052/0459-1879-1998-1-1995-102
PDF
A STUDY OF TRIDIMENSIONAL DOUBLE NONLINEAR DYNAMICS OF DRILLSTRING IN ANNULUS
Based on the analysis of forces and deformations of drillstring with large deflection and intermittent contacts with the well wall,the model of the dynamic frictional contact is improved. Solving the double-nonlinear dynamic problem of drillstring by combinning Wilson-θ method with Newton-Raphson method is developed. The computations show it is possible that various kinds of contact exist togather or alternatively, and that dynamic analysis must be done in higher revolution speed.
1998, 30(1): 96-103. doi: 10.6052/0459-1879-1998-1-1995-103
PDF
A CARTESIAN/TRIANGULAR HYBRID GRID SOLVER FOR COMPLEX INVISCID FLOW FIELDS
A Cartesian/triangular hybrid grid technique is presented for simulating complex inviscid flowfields, where the triangles are limited only close to the solid wall to describe arbitrary complicated curve boundaries,while the Cartesian grids cover almost entire area of interest. A hybrid solver is developed by coupling the non-oscillatory, non-free-parameter dissipative (NND) finite difference scheme and the NND finite volume scheme naturally to match Cartesian/triangular hybrid grids. The present method inhe...
1998, 30(1): 104-108. doi: 10.6052/0459-1879-1998-1-1995-104
PDF
THE EFFECTIVE FRACTURE TOUGHNESS OF MICROCRACKED BODIES 1)
The driving force for the propagation of the macrocrack is reduced by the microcrack zone around the crack tip region of the macrocrack,meanwhile, damage is occurred in the macrocrack tip region, in which the materials is weakened by microcrack damage. Then the fracture toughness of the materials in the macrocrack tip region is decreased. The evaluation of the effect of the microcrack damage on the mechanical behavior must take into account both the stress-shield effect and the decreasing effect of the frac...
1998, 30(1): 109-115. doi: 10.6052/0459-1879-1998-1-1995-105
PDF
THE HEMODYNAMICS MODEL OF CEREBRAL BLOOD AND CEREBROSPINAL FLUID CIRCULATION
The high intracranial pressure (ICP) caused by many disease is very harmful in clinic. The ICP monitoring of patients is one efficient way to control the cerebral hernia, but in the clinical application the ICP accurately monitoring is usually invasive. A noninvasive method for ICP monitoring is highly expected in clinical medicine. According to the investigation of the cerebrovascular, cerebral blood and cerebrospinal fluid dynamics. A hemodynamics model which describes the characteristics of the blood an...
1998, 30(1): 116-120. doi: 10.6052/0459-1879-1998-1-1995-106
PDF
PRELIMINARY INVESTIGATION OF PARTICLE IMAGE VELOCIMETRY (PTV-PIV) TECHNIQUE IN TWO-PHASE FLOW
On the basis of the single phase PTV-PIV investigation, solid-liquid two phase flow field particle image velocimetry technique was studied in this paper. Specially processed Al 2 O 3 powder of 5 μ m was taken as liquid phase tracer, millet of 1.5mm in diameter and 1.265kg/m 3 of density was taken as particle tracer. They were scattered in the circulating water channel to form the experimental two phase flow field. Laser sheet was obtained by using a 45mW He-Ne laser source and a series of mi...
1998, 30(1): 121-125. doi: 10.6052/0459-1879-1998-1-1995-107
PDF

Download Center

Author Center

Copyright © Editorial Office of the Chinese Journal of Mechanics   京ICP备05039218号-1

Address：15 Beishihuan Xi Lu, Haidian District, Beijing, China   China Pos：100190

Tel：010-62536271

Email：lxxb@cstam.org.cn

RSS

Supported by: Beijing Renhe Information Technology Co. Ltd