摘要:

AbstractA new upwind finite element scheme for the incompressible Navier‐Stokes equations at high Reynolds number is presented. The idea of the upwind technique is based on the choice of upwind and downwind points. This scheme can approximate the convection term to third‐order accuracy when these points are located at suitable positions. From the practical viewpoint of computation, the algorithm of the pressure Poisson equation procedure is adopted in the framework of the finite element method. Numerical results of flow problems in a cavity and past a circular cylinder show excellent dependence of the solutions on the Reynolds number. The influence of rounding errors causing Karman vortex shedding is also discussed in the latter prob

ISSN:0271-2091    

DOI:10.1002/fld.1650120402

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe influence of the location of the outflow computational boundary on the unsteady incompressible flow past a circular cylinder at Reynolds number 100 is examined. The vorticity‐streamfunction formulation of the Navier‐Stokes equations is used in all computations. Two types of outflow boundary conditions are subjected to a series of tests in which the domain length is gradually reduced. The traction‐free condition performs well in most cases and allows the outflow boundary to be located as close as 6.5 cylinder diameters from the body. The other boundary condition type is not as forgiving, but has the advantage of being simpler to implement and can still provide reasonably accurate solutions. It is also observed that both condition types can influence the flow field strongly and globally when the boundary is brought closer than 2.5 diameters from the body. In such cases the temporal periodicity of the solution is

ISSN:0271-2091    

DOI:10.1002/fld.1650120403

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA new finite‐element based method of calculating non‐linear wave loads on offshore structures in extreme seas is presented in this paper. The diffraction wave field is modelled using Stokes wave theory developed to second order. Wave loads and free surface elevations are obtained for fixed surface‐piercing structures by solving a boundary value problem for the second‐order velocity potential. Special attention has been given to the radiation condition for the second‐order diffraction field. Results are presented for three test examples, the vertical cylinders of Kim and Yue and of Chakrabarti, and an elliptic cylinder. These results demonstrate that early problems with the application of second‐order theory arising from inadequate radiation conditions have be

ISSN:0271-2091    

DOI:10.1002/fld.1650120404

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThis investigation deals with the modification of streamline curvature effects in thek‐ε turbulence model for the case of recirculating flows. Based upon an idea that the modification of curvature effects inC2should not be made in regions where the streamline curvature is small, a hybridk‐ε model extended from the modification originally proposed by Srinivasan and Mongia is developed. A satisfactory agreement of model predictions with experimental data reveals that the hybridk‐ε model can perform better simulation of recirculating turbule

ISSN:0271-2091    

DOI:10.1002/fld.1650120405

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA finite difference study of the unsteady two‐dimensional flow past a circular cylinder has been conducted using vorticity and streamfunction as the dependent variables. The two cases considered were impulsively started and decelerated flows. The impulsively started problem was considered to validate the method and has yielded results which agree quite closely with existing results from both calculations and experiments. The decelerated flow analysis produced results which can be explained in terms of induced velocity effects from existing wake vortices for both suddenly stopped and uniformly decelerated flow

ISSN:0271-2091    

DOI:10.1002/fld.1650120406

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650120407

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650120408

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650120401

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY