ISSN:0044-2267    

DOI:10.1002/zamm.19970771002

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractIn this work we study error estimates and their respective convergence rates for approximate solution of spectral Galerkin type for the equations of motion of a magneto‐micropolar fluid in a bounded domain. We find error estimates that are optimal in the H1‐norm as well as estimates in the L2‐norm with improved rate with respect to the one immediately derived from the previous H1‐error e

ISSN:0044-2267    

DOI:10.1002/zamm.19970771003

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe unsteady flow of an incompressible viscous fluid over a plane wall in the presence of a body force is considered. Three illustrative examples are given. In the first case, it is assumed that the body force is constant, in the second case the body force depends on time in the form of a positive power of time and in the third case the body force varies sinusoidally in time. In the case of the constant force the displacement and the momentum thickness grow as the square root of time as in the case of the flow due to a flat plate suddenly set in motion. It is shown that there are similarities between the flows considered in this paper and the Stoke's first and second problems.

ISSN:0044-2267    

DOI:10.1002/zamm.19970771004

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractIn the present work, employing the nonlinear equations of an incompressible, isotropic, and elastic body and the exact equations of an incompressible inviscid fluid, the propagation of weakly nonlinear waves in an elastic thick tube filled with an inviscid fluid is studied. The tube is initially assumed to be subjected to a large inner pressureP0and the axial stretch λz, and, in the course of blood flow a large time dependent radial displacement is superimposed on this static field. The nonlinear equation governing the radial motion of the tube is obtained. Utilizing a reductive perturbation technique, the propagation of weakly nonlinear waves is studied and the KdV equation is obtained as the evolution equation. Due to the dependence of the coefficients of the nonlinear evolution equation on initial deformation and the geometrical characteristics it is shown that the solution profile changes with initial deformation and the thickness ratio

ISSN:0044-2267    

DOI:10.1002/zamm.19970771005

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractWe examine theoretically the steady free convection in micropolar fluids. Four different flows, namely, those about a vertical isothermal surface, vertical surface with uniform heat flux, a plane plume and a wall plume are considered in the paper. Numerical solutions for the governing equations are presented, for a range of values of the material properties and Prandtl number of the fluid.

ISSN:0044-2267    

DOI:10.1002/zamm.19970771006

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970771007

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractA numerical method has been performed to explain and interpret oscillating convection phenomena in the vertical zone melting technique. The governing equations are solved in a cylindrical coordinate system using the finite volume method. The thermal boundary conditions were taken from experimental data. The aspect ratio or was varied within the range of 1 ⩽ ar ⩽ 3. Two‐dimensional calculations with application of parabolic boundary temperature show always steady axisymmetric behaviour of the convection. Only the three‐dimensional calculation yields the transition to non‐axisymmetric, time‐dependent (unsteady) flow. Furthermore the necessity of using thermal boundary conditions by a heat flux density q instead of a fixed parabolic temperature profile was demonstrated. The torus‐like flow changes at ar ≃ 1.45…1.5 to a single roll flow pattern. This single roll shows an unsteady behaviour with increasing aspect ratios and Rayleigh numbers, respectively. The comparison of the numerical results with experimental data shows a good qualit

ISSN:0044-2267    

DOI:10.1002/zamm.19970771008

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe compound matrix method is generalized to handle multi‐point boundary‐value problems for first‐order ordinary differential‐equation (ODE) systems. A general treatment is given, covering all dimensions of the linear ODE system and different locations of the linear boundary conditions in a unified way. The back‐propagation step is performed in a new and simplified way. It is shown how local particular solutions can be used for reduction to a homogeneous ODE system. As an application case, efficient techniques are developed for wave‐propagation computations for range‐independent multi‐region fluid‐solid media. Thick homogeneous layers can be handled reliably withou

ISSN:0044-2267    

DOI:10.1002/zamm.19970771009

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractGenericity results for sparse parametric optimization problems with equality and inequality constraints are obtained in this paper. Their impact on path‐following (e.g. load incrementation) methods for discretized elastostatic analysis problems with unilateral contact relations are considered in this paper. For the sparse problems which arise after a finite element method discretization, generically appearing singularities along the path of solutions are classified. Perturbations involving only a minimal number of parameters are shown to be sufficient to guarantee genericity. Stability and uniqueness questions for the solution along the path are examined in this way. These results can be used for the solution of inequality mechanics (unilateral) problems by means of load or displacement incrementation techniques; in particular, the choice of appropriate approximation (e.g. order of finite elements) and of the solution algorithm can be based on the results presented her

ISSN:0044-2267    

DOI:10.1002/zamm.19970771010

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0044-2267    

DOI:10.1002/zamm.19970771011

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY