摘要:

AbstractA method to deal with an open boundary condition in the analysis of water surface waves, the tide, etc. by means of the finite element method is proposed in this paper. The present method has two important features relating to the treatment of the open boundary condition. The first feature is to consider the non‐reflective virtual boundary condition which has been developed in the numerical wave analysis method. The incident wave conditions without spurious reflected waves can be imposed at the open boundary. The second feature is to identify the amplitude of the components of incident waves in terms of observed water elevations in the field of standing waves. This can be done as a parameter identification based on an optimization problem by applying the conjugate gradient method. The applicability of this method to wave propagation problems is verified by several numerical computation

ISSN:0271-2091    

DOI:10.1002/fld.1650130802

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA three‐dimensional control volume finite element method is developed for NAPL groundwater contamination problems. Tetrahedral elements are formed by decomposing deformed blocks. The decomposition is carried out in such a way as to minimize the size of the negative transmissibilities. Negative transmissibilities produce non‐physical discrete fluid flow paths and can cause oscillatory behaviour in the Newton iteration. Example results are presented for a three‐dimensional NAPL contamination scenario using typical geophysical

ISSN:0271-2091    

DOI:10.1002/fld.1650130803

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper presents a composite multigrid method and its application to a geometrically complex flow. The treatment of the interior boundary conditions within a composite multigrid strategy is described in detail for a 1D model equation. For the Navier‐Stokes equations a staggered grid technique is adopted for spatial discretization and a fractional step method is used for the time advance. Lid‐driven cavity flows are used to demonstrate the effectiveness of the met

ISSN:0271-2091    

DOI:10.1002/fld.1650130804

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractRecently, with the advent of supercomputers, there has been considerable interest in the use of direct numerical simulation to obtain information about turbulent shear flow at low Reynolds number. This paper presents a pseudospectral technique to solve the full three‐dimensional time‐dependent Navier‐Stokes and advection‐diffusion equations without the use of subgrid‐scale modelling. The technique has not been previously used for fully developed turbulent channel flow simulation and is based on methods applied in other contexts. The emphasis of this paper is to provide a reasonably detailed account of how the simulation is done rather than to present new calculations of turbulence. The details of an algorithm for turbulent channel flow simulation and the grid and time step sizes needed to integrate through transient behaviour to steady state turbulence have not been published before and are presented here.Results from a Cray‐2 simulation of fully developed turbulent flow in a channel with heat transfer are presented along with a critical comparison between experiment and computation. The first‐ and second‐order moments agree well with experimental measurements; the agreement is poor for higher‐order moments such as the skewness and flatness near the walls of the channel. Detailed information given about the effects of spatial grid resolution on a computed results is important for estimating the size of the computation required to study various aspects of

ISSN:0271-2091    

DOI:10.1002/fld.1650130805

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper presents a numerical technique for the simulation of the effects of grey‐diffuse surface radiation on the temperature field of fluid flows using FIDAP, a general purpose incompressible, viscous fluid code. The radiating surface relationships assume a non‐participating medium, constant surface temperature and heat fluxes at the discretized elemental level.The technique involves the decoupling of energy and radiation exchange equations. A concept of macrosurfaces, each containing a number of radiating boundary surfaces, is introduced. These boundary macroelements then carry the information from the radiating boundary into the fluid regime. A number of simulations illustrating the algorithm are presen

ISSN:0271-2091    

DOI:10.1002/fld.1650130806

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractIn the present paper, limited to the discussion of weak non‐linear shallow water waves, the transmission and reflection of a planar soliton on a two‐dimensional structure are considered. The whole flow field is divided mainly into two subfields. One is in the vicinity of the structure, called the inner field; the other is far from the structure, called the outer field. In the outer field, according to its definition, the influence of the structure on the flow is negligible; to the orderO(α, β) the governing equation for the flow is replaced by the Boussinesq equation. In the inner field the effect of the structure on the flow is significant, so the full Laplace equation is adopted as the governing equation for the flow field. Then the matched asymptotic expansion method is employed to connect smoothly the inner and outer solutions. Owing to the irregularity of the bottom of the structure, the boundary element method is incorporated. As an example, the case in which the incoming wave is a solitary wave is calculated and the time histories of transmitted and reflected waves are pl

ISSN:0271-2091    

DOI:10.1002/fld.1650130807

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650130808

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650130801

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY