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Incompressible Flow Problems (incompressible + flow_problem)

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Engineering	100%

Selected Abstracts

On boundary conditions of the characteristic based split (CBS) algorithm for fluid dynamics

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2002
P. NithiarasuArticle first published online: 12 MAR 200
Abstract This paper discusses alternative procedures which can be used in the application of boundary conditions for the CBS algorithm. Attention is focused on the problem of application of prescribed velocity and traction conditions. The paper is illustrated with some incompressible flow problems. Although previously logical and correct boundary condition specifications were introduced, the procedures outlined in this paper simplify calculations and generally make it more accurate. Copyright © 2002 John Wiley & Sons, Ltd. [source]

New stabilized finite element method for time-dependent incompressible flow problems

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2010
*Article first published online: 20 FEB 200, Yueqiang Shang
Abstract A new stabilized finite element method is considered for the time-dependent Stokes problem, based on the lowest-order P1,P0 and Q1,P0 elements that do not satisfy the discrete inf,sup condition. The new stabilized method is characterized by the features that it does not require approximation of the pressure derivatives, specification of mesh-dependent parameters and edge-based data structures, always leads to symmetric linear systems and hence can be applied to existing codes with a little additional effort. The stability of the method is derived under some regularity assumptions. Error estimates for the approximate velocity and pressure are obtained by applying the technique of the Galerkin finite element method. Some numerical results are also given, which show that the new stabilized method is highly efficient for the time-dependent Stokes problem. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Meshfree weak,strong (MWS) form method and its application to incompressible flow problems

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 10 2004
G. R. Liu
Abstract A meshfree weak,strong (MWS) form method has been proposed by the authors' group for linear solid mechanics problems based on a combined weak and strong form of governing equations. This paper formulates the MWS method for the incompressible Navier,Stokes equations that is non-linear in nature. In this method, the meshfree collocation method based on strong form equations is applied to the interior nodes and the nodes on the essential boundaries; the local Petrov,Galerkin weak form is applied only to the nodes on the natural boundaries of the problem domain. The MWS method is then applied to simulate the steady problem of natural convection in an enclosed domain and the unsteady problem of viscous flow around a circular cylinder using both regular and irregular nodal distributions. The simulation results are validated by comparing with those of other numerical methods as well as experimental data. It is demonstrated that the MWS method has very good efficiency and accuracy for fluid flow problems. It works perfectly well for irregular nodes using only local quadrature cells for nodes on the natural boundary, which can be generated without any difficulty. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Towards entropy detection of anomalous mass and momentum exchange in incompressible fluid flow

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2002
G. F. Naterer
An entropy-based approach is presented for assessment of computational accuracy in incompressible flow problems. It is shown that computational entropy can serve as an effective parameter in detecting erroneous or anomalous predictions of mass and momentum transport in the flow field. In the present paper, the fluid flow equations and second law of thermodynamics are discretized by a Galerkin finite-element method with linear, isoparametric triangular elements. It is shown that a weighted entropy residual is closely related to truncation error; this relationship is examined in an application problem involving incompressible flow through a converging channel. In particular, regions exhibiting anomalous flow behaviour, such as under-predicted velocities, appear together with analogous trends in the weighted entropy residual. It is anticipated that entropy-based error detection can provide important steps towards improved accuracy in computational fluid flow. Copyright © 2002 John Wiley & Sons, Ltd. [source]