摘要:

AbstractVarious techniques for implementing normal and/or tangential boundary conditions in finite element codes are reviewed. The principle of global conservation of mass is used to define a unique direction for the outward pointing normal vector at any node on an irregular boundary of a domain containing an incompressible fluid. This information permits the consistent and unambiguous application of essential or natural boundary conditions (or any combination thereof) on the domain boundary regardless of boundary shape or orientation with respect to the co‐ordinate directions in both two and three dimensions. Several numerical examples are presented which demonstrate the effectiveness of the recommended techniqu

ISSN:0271-2091    

DOI:10.1002/fld.1650020302

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe Boundary Element Method is now well established as a valid numerical technique for the solution of field problems, equal to the Finite Element Method in generality and surpassing it in computational efficiency in some cases.1In this paper is presented a 'Regular Boundary Element Method' as applied to inviscid laminar fluid flow problems. It involves the formation of a system of regular integral equations obtained by moving the singularity outside the domain of the given problem. It is also shown that non‐conforming elements may be used whereby freedoms are not defined at the geometric nodes under the boundary element discretization. A linear element is developed here; higher order variants could easily be defined. Satisfactory numerical results have been obtained using the proposed regular method with both conventional (continuous across the boundary) and non‐conforming boundary elements for two‐dimensional inviscid laminar fluid flow problems having regular and singular solu

ISSN:0271-2091    

DOI:10.1002/fld.1650020303

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA finite‐difference method is described for the numerical integration of the one‐dimensional shallow water equations over a sloping shelf that allows for a continuously moving shoreline. An application of the technique is made to the propagation of non‐breaking waves towards the shoreline. The results of the computation are compared with an evaluation based upon an exact analytical treatment of the non‐linear equations. Excellent agreement is found for both tsunami and tidal scale oscil

ISSN:0271-2091    

DOI:10.1002/fld.1650020304

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe problem of truncating nearshore finite element wave models is addressed. Incorrect treatment of the artificial boundaries of the model will cause spurious wave reflections. Three methods for dealing with these boundaries: application of constraints, use of the Smith condition and longshore dampers, are proposed. Numerical results show the dampers to be the best method.

ISSN:0271-2091    

DOI:10.1002/fld.1650020305

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractSpace‐time finite element solutions of the convection–dispersion equation using higher‐order nodal continuity and Hermitian polynomial shape functions are described. Five separate elements ranging from a complete linear element withC0,0nodal continuity to a complete first‐order Hermitian element withC1,1nodal continuity are subjected to detailed analysis. Wave deformation analyses identify the source of leading or trailing edge oscillations, trailing edge oscillations being the major source of difficulty. These observations are confirmed by numerical experiments which further demonstrate the potential of higher‐order nodal continuity. The performance of the complete first‐order Hermitian element is quite satisfactory and measurably superior to the lin

ISSN:0271-2091    

DOI:10.1002/fld.1650020306

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractHamilton's variational principle is applied to derive a system of conditions which expresses the balance of momentum and energy of an ideal gas across the selvadgesThe reviewer of this paper confesses to be unfamiliar with the term 'selvadge(s)' which appears frequently herein. Clearly, however, it (variously) means 'boundary', 'edge', 'projection of edge line' (meridional or axial), 'locus of leading edges', etc.of bladed zones within the flow tracts of turbines. This system provides the background for a correct formulation of optimal design problems for turbines and compressors. The exposition follows the model of a large number of blades when the basic equations can be averaged over the azimuthal co‐ordinate.An analysis is given of the obtained conditions and a computational algorithm describe

ISSN:0271-2091    

DOI:10.1002/fld.1650020307

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650020308

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650020301

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY