摘要:

AbstractWe investigate the magnetohydrodynamic flow (MHD) on the upper, half of a non‐conducting plane for the case when the flow is driven by the current produced by an electrode placed in the middle of the plane. The applied magnetic field is perpendicular to the plane, the flow is laminar, uniform, steady and incompressible. An analytical solution has been developed for the velocity field and the induced magnetic field by reducing the problem to the solution of a Fredholm's integral equation of the second kind, which has been solved numerically. Infinite integrals occurring in the kernel of the integral equation and in the velocity and magnetic field were approximated for large Hartmann numbers by using Bessel functions. As the Hartmann numberMincreases, boundary layers are formed near the non‐conducting boundaries and a parabolic boundary layer is developed in the interface region. Some graphs are given to show examples of this behavi

ISSN:0271-2091    

DOI:10.1002/fld.1650080702

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAn accurate numerical scheme has been devised to study the self‐induced motion of an infinitely thin, free vortex sheet of finite span in an unbounded, inviscid, incompressible fluid. The new numerical scheme has been tested against two vortex sheet problems for which exact solutions have also been obtained. The agreement between the numerical and exact solutions is excellent. The scheme has been further tested against two more examples for which analytical solutions for small times were available. Here too the agreement is excellen

ISSN:0271-2091    

DOI:10.1002/fld.1650080703

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA role of numerical methods in engineering research is illustrated in the present work, namely the use of computer algorithms as experimental facilities. A complex recirculating flow in a three‐dimensional cavity was simulated and an extensive data base was generated which complements data measured in concurrent physical experiments. The objective of this numerical investigation was to improve understanding of physical phenomena in recirculating flows. The dominant physical phenomena in this shear‐driven flow simulation are Taylor‐Görtler vortices. These structures are intimately coupled with the primary recirculating flow and the effects of end‐wall viscous

ISSN:0271-2091    

DOI:10.1002/fld.1650080704

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper describes the characteristics of small‐amplitude waves generated by a sinusoidally oscillating, inclined paddle‐type wavemaker operating in a constant‐depth channel. Two‐dimensional, linearized potential flow is assumed. A semi‐analytical method, the boundary collocation method, is used to establish the relationship between wave amplitude and paddle stroke. The numerical results are compared with the numerical results of the boundary integral equation method. It is found that the boundary collocation method is simpler and more flexible to implement and faster to compute. In addition, the numerical results are in reasonably good agreement with the laboratory experimental data. For the vertical wavemaker, which is a special case of the inclined wavemaker, an analytical series solution can be found. By using the boundary collocation method and the boundary integral equation method to solve the vertical wavemaker problem and comparing the results with the analytical series solution, it is found that the boundary collocation method yields a solution which is much more accurate than that from the boundary integral equation method. Finally, the relationships between wave amplitude and paddle stroke are established for different inclinations of the paddle‐type wavemaker, based on the boundary colloca

ISSN:0271-2091    

DOI:10.1002/fld.1650080705

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAn iterative type harmonic finite element model is developed for solving the full non‐linear form of the shallow water equations. The scheme iteratively updates time histories of the non‐linear terms which are then harmonically decomposed and used as forcing terms for the linear sets of equations which result from the harmonic separation of the shallow water equations.A least‐squares harmonic analysis procedure is used to decompose the non‐linear forcing terms. This procedure allows for the very efficient separation of extremely closely spaced harmonics, since it is highly selective with respect to the frequencies it considers. In addition tailoring the procedure and using very specific time steps and sampling periods significantly reduces the number of time samplings points required. In conjunction with the iterative nature of our scheme, the least‐squares procedure makes the scheme entirely general, allows for the direct assessment of all tidal constituents, including compound tides, and permits the clear cut and complete investigation of their mutual interaction through the non‐linearities. In addition this procedure readily computes very‐low‐frequency or residual type circulations.The FE formulation used shows a very low degree of spurious oscillations while remaining quite simple to implement. This control on nodal oscillations is especially important due to the energy transfer mechanisms involved in this type of iterative scheme.In an example application the effects of the various non‐linear overtide and compound tide type interactions are examined. It is demonstrated that not only are compound tides significant relative to the overtides, but they also influe

ISSN:0271-2091    

DOI:10.1002/fld.1650080706

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractTwo numerical methods, the Galerkin finite element method (FEM) and the boundary‐fitted co‐ordinate transformation method (BFCTM), have been applied to solve inelastic non‐Newtonian fluid flow in ducts of irregular cross‐section. Three representative fluid models, namely the power‐law, the Ellis and the Bingham models, have been analysed. The application of the FEM is straightforward, while for the BFCTM the accurate estimation of viscosity on the duct boundary and the proper mesh adjustment appear to be critical for generating convergent solutions. A detailed comparison of the two numerical methods in terms of volumetric flow rate, axial velocity, shear rate, viscosity and CPU time is given. Both methods can generate accurate solutions of velocity over a wide range of variables, but the FEM requires much less computing time to reach the same level of accuracy. Only the BFCTM can be used to approximate shear rate and viscosity with reasonable

ISSN:0271-2091    

DOI:10.1002/fld.1650080707

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650080708

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650080709

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650080701

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY