A global Stokes method of approximated particular solutions for unsteady two-dimensional Navier–Stokes system of equations

J. M. Granados, C. A. Bustamante, H. Power, W. F. Florez

    Research output: Contribution to journalArticlepeer-review

    7 Scopus citations

    Abstract

    The unsteady two-dimensional Navier–Stokes system of equations, for viscous incompressible fluids are solved using a global method of approximated particular solutions (MAPS) in terms of a Stokes formulation, where the velocity and pressure fields are approximated from a linear superposition of particular solutions of a non-homogeneous Stokes system of equations, with a multiquadric (MQ) radial basis function (RBF) as non-homogeneous term. Steady-state solution of the flow problems considered in this work can be unstable at high Reynolds numbers (Re), corresponding to bifurcation of solutions that result in the appearance of new stable steady-state or periodic solutions. The main objective of this work is to present a global meshless numerical scheme able to predict these bifurcation points and concurrent new stable or periodic solutions. This is well known to be a very difficult task for any numerical scheme. An implicit first-order time-stepping scheme is used to approximate the transient term and the obtained nonlinear system of algebraic equations is solved by a Newton–Raphson method with variable step. Two steady-state and two transient problems are considered to validate the numerical scheme: the lid-driven cavity and backward-facing step (BFS) flows (steady-state problems) and the decaying Taylor–Green vortex and two-sided lid-driven cavity flows (transient problems). The first two problems are solved up to Re=10,000 and 2300, respectively. Results obtained are compared with corresponding benchmark numerical solutions, showing excellent agreement. Obtained numerical solutions for the decaying vortices at Re=100 shown excellent agreement with the corresponding analytical results. The transient problem of a rectangular two-sided lid-driven cavity flow is solved at Re=700. The influence of the cavity length, l, in determining the different structures of the flow pattern is studied for values of (Formula presented.), showing that the scheme is able to reproduce the previously reported change in the flow pattern when l=2. Finally, the global Stokes MAPS are used to carry out nonlinear stability analyses of three steady-state problems: the sudden expansion, lid-driven cavity and BFS flows. Stable and unstable steady-state solutions at Re values greater than critical are predicted with the proposed numerical scheme. Our numerical results are consistent with previously stability analysis reported in the literature.

    Original languageEnglish
    Pages (from-to)1515-1541
    Number of pages27
    JournalInternational Journal of Computer Mathematics
    Volume94
    Issue number8
    DOIs
    StatePublished - 3 Aug 2017

    Bibliographical note

    Funding Information:
    This work was supported by COLCIENCIAS by means of the PhD Student supporting program.

    Publisher Copyright:
    © 2016 Informa UK Limited, trading as Taylor & Francis Group.

    Keywords

    • instability
    • meshless method
    • Navier–Stokes equations
    • radial basis functions
    • Stokes particular solutions

    Fingerprint

    Dive into the research topics of 'A global Stokes method of approximated particular solutions for unsteady two-dimensional Navier–Stokes system of equations'. Together they form a unique fingerprint.

    Cite this