摘要:

AbstractA study of viscous and inviscid hypersonic flows using generalized upwind methods is presented. A new family of hybrid flux‐splitting methods is examined for hypersonic flows. The hybrid method is constructed by the superposition of the flux‐vector‐splitting (FVS) method and second‐order artificial dissipation in the regions of strong shock waves. The conservative variables on the cell faces are calculated by an upwind extrapolation scheme to third‐order accuracy. A second‐order‐accurate scheme is used for the discretization of the viscous terms. The solution of the system of equations is achieved by an implicit unfactored method. In order to reduce the computational time, a local adaptive mesh solution (LAMS) method is proposed. The LAMS method combines the mesh‐sequencing technique and local solution of the equations. The local solution of either the Euler or the NAVIER‐STOKES equations is applied for the region of the flow field where numerical disturbances die out slowly. Validation of the Euler and NAVIER‐STOKES codes is obtained for hypersonic flows around blunt bodies. Real gas effects are introduced via a generalize

ISSN:0271-2091    

DOI:10.1002/fld.1650160902

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper summarizes a combined analytical‐computational technique which models vortex sheets in transonic potential‐flow methods. In this approach, the inviscid nature of discontinuities across vortex sheets is preserved by employing the step function to remove singularities at these surfaces. The location and strength of the vortex sheets are determined by satisfying the flow‐tangency boundary condition and the vorticity transport equation. The theory is formulated for the general three‐dimensional case, but its application is confined to the problem of computing slipstreams behind propellers with free‐vortex blading in axisymmet

ISSN:0271-2091    

DOI:10.1002/fld.1650160903

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper describes a three‐step finite element method and its applications to unsteady incompressible fluid flows. Stability analysis of the one‐dimensional pure convection equation shows that this method has third‐order accuracy and an extended numerical stability domain in comparison with the Lax‐‐Wendroff finite element method. The method is cost‐effective for incompressible flows because it permits less frequent updates of the pressure field with good accuracy. In contrast with the Taylor‐Galerkin method, the present method does not contain any new higher‐order derivatives, which makes it suitable for solving non‐linear multidimensional problems and flows with complicated boundary conditions. The three‐step finite element method has been used to simulate unsteady incompressible flows. The numerical results obtained are in good agreement with thos

ISSN:0271-2091    

DOI:10.1002/fld.1650160904

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe formation of large gas bubbles at submerged orifices is investigated numerically with a two‐dimensional, transient, finite difference model using a volume fraction specification to track the movement of the gas‐liquid interface. Experimentally observed features of large‐bubble formation such as the initial toroidal shape of the bubbles and the penetration of liquid down the pipe centreline are well predicted by the model. The expected oscillatory nature of growth is also observed. The bubble departure volume corresponds to experiments and to the model of Davidson and Schuler. At present the simulations do not extend far enough to investigate multiple‐bubble ejection and important bubble‐to‐bubble interactions during growth and afte

ISSN:0271-2091    

DOI:10.1002/fld.1650160905

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA new method is presented for the solution of free‐boundary problems using Lagrangian finite element approximations defined on locally refined grids. The formulation allows for direct transition from coarse to fine grids without introducing non‐conforming basis functions. The calculation of elemental stiffness matrices and residual vectors are unaffected by changes in the refinement level, which are accounted for in the loading of elemental data to the global stiffness matrix and residual vector. This technique for local mesh refinement is combined with recently developed mapping methods and Newton's method to form an efficient algorithm for the solution of free‐boundary problems, as demonstrated here by sample calculations of cellular interfacial microstructure during directional solidification of a binary

ISSN:0271-2091    

DOI:10.1002/fld.1650160906

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper presents a formulation of the boundary element method (BEM) for solution of axisymmetric cavity flow problems. The governing equation is written in terms of Stokes' stream function, requiring a new fundamental solution to be found. The iterative procedure for adjusting the free‐surface position is similar to that used for planar cavity flows. Numerical results are compared with finite difference and finite element solutions, showing the robustness of the BEM mode

ISSN:0271-2091    

DOI:10.1002/fld.1650160907

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650160908

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650160901

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY