摘要:

AbstractA unified approach is presented for solving the two‐dimensional incompressible boundary layer equations. Solutions are obtained for direct and inverse options using the same equation formulation by a simple interchange of boundary conditions. A modified form of the mechul function scheme obtains inverse solutions with specification of transformed wall shear, skin friction coefficient or displacement thickness distributions. Direct solutions may be obtained without altering the block tridiagonal structure of the system by simply requiring no corrections on the streamwise pressure gradient parameter. Fourth‐order spline discretization approximates normal derivatives with two‐ and three‐point backward differences approximating streamwise derivatives, yielding a fully implicit solution method. The resulting spline/finite difference equations are solved by Newton‐Raphson iteration together with partial pivoting. The results of the study demonstrate the importance of proper linearization of all equations. The successful use of spline discretization is also tied to the use of strong two‐point boundary conditions at the wall for cases involving reversed flow. Numerical solutions are presented for several non‐similar flows and compared with publ

ISSN:0271-2091    

DOI:10.1002/fld.1650081102

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper concerns the applications of frontal advance theory to the dynamics of a moving flat interface in a porous medium, when both displacing and displaced fluids are of power law behaviour. The rheological effects of non‐Newtonian behaviour of these fluids on the interface position and its velocity are numerically illustrated and discussed with regard to the practical implications in oil displacement mechanisms. The results obtained should be useful in finding an optimal policy of injection in order to control the dynamics of the moving interface in field projects of enhanced oil recovery flood

ISSN:0271-2091    

DOI:10.1002/fld.1650081103

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA numerical study is made of the unsteady two‐dimensional laminar flow of an incompressible fluid over a periodically grooved wall. Two independent finite difference techniques are employed. One is based on the vorticity‐stream function and the other on the vorticity‐velocity (i.e. induction law) formulation. The fluid motion is initiated impulsively from rest and is assumed to be spatially periodic in the streamwise direction. The numerical formulations are derived in detail. The generation of vorticity at the solid surface is modelled differently in the two approaches, and this is found to play an important role in determining the surface pressure distribution and the drag coefficient. The flow field is examined during the early transient phase of development, during which the greatest changes occur. Results are presented for a moderate Reynolds number (based on groove depth) equal to 100. It is found that the vorticity‐stream function approach does not produce a spatially periodic wall pressure distribution, and therefore global conservation of total vorticity is not achieved. This results in substantial errors in the predictions for the drag coefficient. These deficiencies are not found in the results obtained by the vorticity‐velocity fo

ISSN:0271-2091    

DOI:10.1002/fld.1650081104

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe accuracy of a deterministic particle method in approximating the solution of the Navier‐Stokes equations is investigated. The convective part is solved using a classical vortex method for inviscid fluids, and an iterative procedure is added to improve the interpolation of the vorticity function. In our examples the vorticity is radially symmetric. For a regular initial data, a discrete quadratic error on the velocity and the vorticity is considered. Otherwise, for a singular initial data, the exact and computed angular moments of the vorticity are compare

ISSN:0271-2091    

DOI:10.1002/fld.1650081105

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThis work comments on a recent paper by J. C. Strikwerda inSIAM Journal on Scientific and Statistical Computing, in an attempt to clear up the evident confusion regarding the use of a Poisson equation for pressure in incompressible Navier‐Stokes solution

ISSN:0271-2091    

DOI:10.1002/fld.1650081106

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650081107

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650081108

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650081101

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY