International Journal for Numerical Methods in Fluids

Cover image for Vol. 71 Issue 4

10 February 2013

Volume 71, Issue 4

Pages 403–536

  1. Research Articles

    1. Top of page
    2. Research Articles
    1. Depth-integrated free-surface flow with parameterized non-hydrostatic pressure (pages 403–421)

      Yefei Bai and Kwok Fai Cheung

      Version of Record online: 13 MAR 2012 | DOI: 10.1002/fld.3664

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      The common approach to improve the dispersion properties of non-hydrostatic models has been to increase the number of layers, thereby multiplying the bandwidth and rank of the resulting matrix equation. The present paper proposes a parameterized non-hydrostatic pressure distribution that improves dispersion through a two-layer formulation while maintaining the same matrix bandwidth and rank as in a one-layer model. In coastal engineering applications, the proposed model produces comparable results to a conventional two-layer model at the computational requirement of a one-layer model. The approach can be extended to multi-layer models to form an alternate class of non-hydrostatic models for free surface flow.

    2. An efficient algorithm based on the differential quadrature method for solving Navier–Stokes equations (pages 422–445)

      S. Hamed Meraji, Abbas Ghaheri and Parviz Malekzadeh

      Version of Record online: 12 MAR 2012 | DOI: 10.1002/fld.3665

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      In this paper, an approach to improve the application of the differential quadrature method for the solution of Navier-Stokes equations is presented. In using the conventional differential quadrature method for solving Navier-Stokes equations, difficulties such as boundary conditions' implementation, generation of an ill-conditioned set of linear equations, large memory storage requirement to store data, and matrix coefficients are usually encountered.

    3. Unified semi-analytical wall boundary conditions for inviscid, laminar or turbulent flows in the meshless SPH method (pages 446–472)

      M. Ferrand, D. R. Laurence, B. D. Rogers, D. Violeau and C. Kassiotis

      Version of Record online: 20 MAR 2012 | DOI: 10.1002/fld.3666

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      The authors propose a new framework for modelling the boundary conditions in SPH using neither dummy particles nor artificial forces. The new formulation is more consistent than the existing models in the literature and gives results in agreement with mesh-based methods for complex flows including turbulent (Reynolds-averaged) models.

    4. Review of wetting and drying algorithms for numerical tidal flow models (pages 473–487)

      Stephen C. Medeiros and Scott C. Hagen

      Version of Record online: 22 MAR 2012 | DOI: 10.1002/fld.3668

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      This paper reviews numerical wetting and drying algorithms for fixed grid, numerical tidal flow models. They typically fall into one of four categories: Thin film, element removal, depth extrapolation, and negative depth. The ability of the models and their associated wetting and drying algorithms to conserve mass and capture the physics at the wetting front is discussed.

    5. Stability of algebraic multigrid for Stokes problems (pages 488–505)

      Ronald Webster

      Version of Record online: 11 APR 2012 | DOI: 10.1002/fld.3672

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      The stability of smoothing in algebraic multigrid solvers, when applied to strongly coupled field problems (saddle-point problems), is shown to depend on the degree of coarsening in the coarse-grid approximation (CGA). Stability is most fragile for CGAs constructed with inter-grid transfer operators based on an equal-order interpolation of the scalar and vector fields. The ability of CGAs based on mixed-order interpolation to provide for a stable smoothing, and hence a mesh-independent convergence, is explained.

    6. Building generalized open boundary conditions for fluid dynamics problems (pages 506–521)

      Eric Blayo and Véronique Martin

      Version of Record online: 17 APR 2012 | DOI: 10.1002/fld.3675

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      This paper deals with the design of an efficient open boundary condition (OBC) for fluid dynamics problems. Such problems arise, for instance, when one solves a local model on a fine grid that is nested in a coarser one of greater extent. We propose OBCs on the basis of absorbing boundary conditions or Richardson extrapolation. Numerical test cases on a 1D Laplace equation and on a 1D shallow water system illustrate the improved efficiency of such a generalized OBC compared with usual ones.

    7. Towards simulation of flapping wings using immersed boundary method (pages 522–536)

      X. Q. Zhang, P. Theissen and J. U. Schlüter

      Version of Record online: 17 APR 2012 | DOI: 10.1002/fld.3678

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      A Lagrangian method is developed to approximate the solution on the freshly cleared cells occurring in the simulation of moving objects using immersed boundary method. The method is validated on a stationary/moving cylinder. The main focus is on the study of evolution of leading edge vortex around a rapidly pitching flat plate and its effect on the lift and drag coefficients at a set of angles of attack and Reynolds numbers.