ISSN:0271-2091    

DOI:10.1002/fld.1650141202

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe influence of artificial dissipation schemes on the accuracy and stability of the numerical solution of compressible flow is extensively examined. Using an implicit central difference factored scheme, an improved form of artificial dissipation is introduced which highly reduces the errors due to numerical viscosity. A function of the local Mach number is used to scale the amount of numerical damping added into the solution according to the character of the flow in several flow regimes. The resulting scheme is validated through several inviscid flow test cases.

ISSN:0271-2091    

DOI:10.1002/fld.1650141203

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAn adaptive finite element scheme for transient problems is presented. The classic h‐enrichment/coarsening is employed in conjunction with a tetrahedral finite element discretization in three dimensions. A mesh change is performed every n time steps, depending on the Courant number employed and the number of ‘protective layers’ added ahead of the refined region. In order to simplify the refinement/coarsening logic and to be as fast as possible, only one level of refinement/coarsening is allowed per mesh change. A high degree of vectorizability has been achieved by pre‐sorting the elements and then performing the refinement/coarsening groupwise according to the case at hand. Further reductions in CPU requirements arc realized by optimizing the identification and sorting of elements for refinement and deletion. The developed technology has been used extensively for shock‐shock and shock‐object interaction runs in a production mode. A typical example of this class of proble

ISSN:0271-2091    

DOI:10.1002/fld.1650141204

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA procedure which ensures the elimination of discretization and coding errors in the numerical solution of a set of governing equations describing internal turbulent convection flows is given and illustrated. The governing equations investigated in the validation analysis are of general form. The equations for the turbulence model (k‐8) assume the turbulence to be isotropic. In the analysis a portion of the solution region uses a Lagrangian description while a Eulerian description is used elsewhere. The work was originally motivated by the need to validate numerical calculations performed in the modelling of cornbusting fluid flow within symmetric piston engines. Thus the procedure is demonstrated for an axisymmetric formulation. The same methodology can be even more easily applied to Cartesian‐based problems using the guidelines given in this work. Details of the procedure are presented in a very practical format, making it possible to consider both simpler and more complex governing equation sets with little additional effort. Thus the implementation of this procedure by researchers to a variety of both turbulent and laminar internal flow problems should prove to be e

ISSN:0271-2091    

DOI:10.1002/fld.1650141205

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA new computational approach is developed for the analysis of vortex‐dominated flow fields around highly swept wings at high angles of attack. In this approach an inviscid Euler technology is coupled with viscous models, similar to inviscid/boundary layer coupling. The viscous nature of the vortex core is represented by an algebraic model derived from the Navier–Stokes equations. The approach also accounts for the effects of the viscous shear layer near a wing surface through a modified surface boundary condition. The inviscid/viscous coupling consistently provides improved predictions of leading edge separation, vortex bursting and secondary vortex formation at relatively low computational cost. Results for several cases are compared with wind tunnel tests and other Euler and Navier‐Stokes solu

ISSN:0271-2091    

DOI:10.1002/fld.1650141206

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper describes a Biot–Savart discrete vortex model for simulating the flow patterns which occur when a single high‐velocity inflow jet is used to stir the fluid within a circular container. The first stage of the model consists of conformally mapping the circular perimeter of the container onto a rectangle by means of a Schwarz–Christoffel transformation. A potential flow solution is then obtained for the flow inside the rectangle and this is transformed to give the potential flow inside the circle. In the second stage of the simulation, discrete vortices are added at the inlet of the physical system in order to model the inflow shear layers. Velocity components resulting from the discrete vortices and their images in the walls of the cylinder are superimposed on the uniform potential flow solution. The positions of the vortices are updated using a Lagrangian tracking procedure. Viscous effects are incorporated through the use of random walks. From the results it is shown that the discrete vortex method does predict qualitatively the important features of jet‐forced reservo

ISSN:0271-2091    

DOI:10.1002/fld.1650141207

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe structure of confined wakes behind a square cylinder in a channel is investigated via the numerical solution of the unsteady Navier–Stokes equations. Vortex shedding behind the cylinder induces periodicity in the flow field. Details of the phenomenon are simulated through numerical flow visualization. The unsteady periodic wake can be characterized by the Strouhal number, which varies with the Reynolds number and the blockage ratio of the channel. The periodicity of the flow is, however, damped in the downstream region of a long duct. This damping may be attributed to the influence of side walls on the flow structur

ISSN:0271-2091    

DOI:10.1002/fld.1650141208

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper describes a numerical study of laminar flow through building cracks such as those found around doors or windows. The mathematical model is based on the solution of the two‐dimensional conservation equations of mass and momentum by a finite volume method. The results are presented for two crack geometries, namely double‐bend and four‐bend cracks. The variation in local pressure coefficient along the crack walls and the velocity and pressure distributions within the cracks are described. The overall predicted pressure coefficient for the double‐bend crack for the double‐bend crack is compared with the results obtained using a correlation given by Bak

ISSN:0271-2091    

DOI:10.1002/fld.1650141209

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650141210

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650141201

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY