摘要:

AbstractA finite element solution of the two‐dimensional incompressible Navier–Stokes equations has been developed. The present method is a modified velocity correction approach. First an intermediate velocity is calculated, and then this is corrected by the pressure gradient which is the solution of a Poisson equation derived from the continuity equation. The novelty, in this paper, is that a second‐order Runge–Kutta method for time integration has been used. Discretization in space is carried out by the Galerkin weighted residual method. The solution is in terms of primitive variables, which are approximated by polynomial basis functions defined on three‐noded, isoparametric triangular elements. To demonstrate the present method, two examples are provided. Results from the first example, the driven cavity flow problem, are compared with previous works. Results from the second example, uniform flow past a cylinder, are compared with experime

ISSN:0271-2091    

DOI:10.1002/fld.1650170502

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis paper presents the development of a parabolic numerical procedure for rotating flows and its applications to three‐dimensional viscous rotating flows. The formulation is based on the Navier–Stokes equations in general co‐ordinates fixed on a rotating frame, so that the rotation effect is included in the guess‐correct process. The use of body‐fitted curvilinear co‐ordinates makes it easier to handle the complex geometries of turbomachinery components. In the present work ak–ϵ turbulence model was used for the three‐dimensional numerical tests. The algorithm is equally applicable to incompressible and compressible flows. Comparisons of the predicted results with the experimental data were reasonably good, and the solutions were stable to rotational speeds up to at

ISSN:0271-2091    

DOI:10.1002/fld.1650170503

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA pressure correction formula is proposed for the SIMPLE‐like algorithm in order to improve the rate of the convergence when solving laminar Navier–Stokes equations when there is rapidly varying pressure. Based on global mass conservation, a line average pressure correction is derived by integration of the momentum equation for approximate one‐dimensional flow. The use of this formula with the SIMPLE‐like algorithm can rapidly build up the pressure distribution in the region where the pressure undergoes a very large change, which normally causes the rate of convergence of the SIMPLE or the SIMPLEC schemes to be slow. In order to illustrate the technique, the performances of SIMPLE and of SIMPLEC with the average pressur correction are investigated for axisymmetric flow past and through a sampler. A comparison of these two techniques shows that the average pressure correction proposed in this paper significantly accelerates the rate of conv

ISSN:0271-2091    

DOI:10.1002/fld.1650170504

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn this paper the problem of impulsively started aerofoil or suden change of incidence of an aerofoil in incompressible potential flow is investigated. The essence of solution lies in the representation of a timely and spatially varying wake in a largely irrotational potential flow field. This is achieved by representing the wake through velocity potential difference, which seems to be the only way of imposing a velocity difference condition in the finite element context with velocity potentials as the basic unknowns. Superposition is employed to meet various boundary conditions, which is justified by the linearity of the problem. The finite element solutions are compared with those from singularity method.

ISSN:0271-2091    

DOI:10.1002/fld.1650170505

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractMost receiving water, such as lakes and open reservoirs, have large plan dimensions with respect to their depth. In such cases, the flow may be nearly two‐dimensional and the depth‐averaged Reynolds equations are appropriate. This paper presents a new version of the governing equations in curvilinear depth‐averaged stream function and vorticity transport (ψ, ω) form appropriate for non‐orthogonal computational meshes. The equations are discretized using finite differences and solved using successive over‐relaxation for the depth‐averaged stream function equation and an alternating direction implicit scheme for the vorticity transport equation. Results from the numerical model are validated against data from flow past a backward facing step and jet‐forced flow in a circular reservoir. The results indicate that the (ψ, ω) form of the shallow water equations may be useful for applications where the free surface can either be assumed horizontal, o

ISSN:0271-2091    

DOI:10.1002/fld.1650170506

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650170507

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650170501

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY