François Bouchon^{1, *}, Thierry Dubois¹, Nicolas James²

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 165-184, 2019, DOI:10.32604/cmes.2019.04841

Abstract We present a cut-cell method for the simulation of 2D incompressible flows past obstacles. It consists in using the MAC scheme on cartesian grids and imposing Dirchlet boundary conditions for the velocity field on the boundary of solid structures following the Shortley-Weller formulation. In order to ensure local conservation properties, viscous and convecting terms are discretized in a finite volume way. The scheme is second order implicit in time for the linear part, the linear systems are solved by the use of the capacitance matrix method for non-moving obstacles. Numerical results of flows around an impulsively started circular cylinder are… More >

C. Shu^1,2, H. Ding², K.S. Yeo²

CMES-Computer Modeling in Engineering & Sciences, Vol.7, No.2, pp. 195-206, 2005, DOI:10.3970/cmes.2005.007.195

Abstract Local radial basis function-based differential quadrature (RBF-DQ) method was recently proposed by us. The method is a natural mesh-free approach. It can be regarded as a combination of the conventional differential quadrature (DQ) method with the radial basis functions (RBFs) by means of taking the RBFs as the trial functions in the DQ scheme. With the computed weighting coefficients, the method works in a very similar fashion as conventional finite difference schemes. In this paper, we mainly concentrate on the applications of the method to incompressible flows in the steady and unsteady regions. The multiquadric (MQ) radial basis functions are… More >

Alfredo Nicolás¹, Blanca Bermúdez²

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.5, pp. 441-452, 2004, DOI:10.3970/cmes.2004.006.441

Abstract 2D incompressible vicous flows from the unsteady Navier-Stokes equations in stream function-vorticity variables are presented. The results are obtained using a simple numerical procedure based on a fixed point iterative process to solve the nonlinear elliptic system that results once a second order time discretization is performed. Flows on the unregularized unit driven cavity are reported up to Reynolds numbers Re=5000 to compare them with those reported by other authors and supposed to be correct. Various long time computations are presented for Re=10000 to see its evolution as time-dependent flow. Moreover, results are reported for Re=10000, Re=15000 and Re=20000 to… More >

J.S. Ren^*

Molecular & Cellular Biomechanics, Vol.7, No.4, pp. 213-224, 2010, DOI:10.3970/mcb.2010.007.213

Abstract Dynamic analysis of an axially stretched arterial wall with collagen fibers distributed in two preferred directions under a suddenly applied constant internal pressure along with the possibility of the formation and rupture of aneurysm are examined within the framework of nonlinear dynamics. A two layer tube model with the fiber-reinforced composite-based incompressible anisotropic hyper-elastic material is employed to model the mechanical behavior of the arterial wall. The maximum amplitudes and the phase diagrams are given by numerical computation of the differential relation. It is shown that the arterial wall undergoes nonlinear periodic oscillation and no aneurysms are formed under the… More >

J. S. Ren^*

Molecular & Cellular Biomechanics, Vol.4, No.1, pp. 55-66, 2007, DOI:10.3970/mcb.2007.004.055

Abstract Formation and rupture of aneurysms due to the inflation of an artery with collagen fibers distributed in two preferred directions, subjected to internal pressure and axial stretch are examined within the framework of nonlinear elasticity. A two layer tube model with a fiber-reinforced composite based incompressible anisotropic hyperelastic constitutive material is employed to model the stress-strain behavior of the artery wall with distributed collagen fibers. The artery wall takes up a uniform inflation deformation, and there are no aneurysms in the artery under the normal condition. But an aneurysm may be formed in arteries when the stiffness of the fibers… More >

X.G. Yuan^1,2, R.J. Zhang²

CMC-Computers, Materials & Continua, Vol.2, No.3, pp. 201-212, 2005, DOI:10.3970/cmc.2005.002.201

Abstract Cavity formation and growth in a class of incompressible transversely isotropic nonlinearly elastic solid spheres are described as a bifurcation problem, for which the strain energy density is expressed as a nonlinear function of the invariants of the right Cauchy-Green deformation tensor. A bifurcation equation that describes cavity formation and growth is obtained. Some interesting qualitative properties of the bifurcation equation are presented. In particular, cavitated bifurcation is examined for a solid sphere composed of an incompressible anisotropic Gent-Thomas material model with a transversely isotropy about the radial direction. The effect of constitutive parameters on cavity formation and growth is… More >

Weiwei Zhang¹, Yufeng Nie¹, Li Cai¹, Nan Qi²

CMES-Computer Modeling in Engineering & Sciences, Vol.102, No.1, pp. 55-82, 2014, DOI:10.3970/cmes.2014.102.055

Abstract In this paper, we derive an adaptive mesh generation method for discretizing the incompressible flow using node-based local grids. The flow problem is described by the Stokes equations which are solved by a stabilized low-order P1-P1 (linear velocity, linear pressure) mixed finite element method. The proposed node-based adaptive mesh generation method consists of four components: mesh size modification, a node placement procedure, a node-based local mesh generation strategy and an error estimation technique, which are combined so as to guarantee obtaining a conforming refined/coarsened mesh. The nodes are considered as particles with interaction forces, which are generated by dynamic simulation… More >

D. Ishihara¹, T. Horie¹

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.6, pp. 421-440, 2014, DOI:10.3970/cmes.2014.101.421

Abstract In this study, a projection method for the monolithic interaction system of an incompressible fluid and a structure using a new algebraic splitting is proposed. The proposed method splits the monolithic equation system into the equilibrium equations and the pressure Poisson equation (PPE) algebraically using the intermediate velocity in the nonlinear iterations. Since the proposed equilibrium equation satisfies the interface condition, the proposed method is strongly coupled. Moreover, the proposed PPE enforces the incompressibility constraint. Different from previous studies, the proposed algebraic splitting never generates any Schur complement. The proposed method is applied to a channel with a flexible flap,… More >

B. Pekmen^1,2, M. Tezer-Sezgin^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.4, pp. 275-292, 2013, DOI:10.3970/cmes.2013.096.275

Abstract The dual reciprocity boundary element method (DRBEM) formulation is presented for solving incompressible magnetohydrodynamic (MHD) flow equations. The combination of Navier-Stokes equations of fluid dynamics and Maxwell’s equations of electromagnetics through Ohm’s law is considered in terms of stream function, vorticity and magnetic potential in 2D. The velocity field and the induced magnetic field can be determined through the relations with stream function and magnetic potential, respectively. The numerical results are visualized for several values of Reynolds (Re), Hartmann (Ha) and magnetic Reynolds number (Rem) in a lid-driven cavity, and in a channel with a square cylinder. The well-known characteristics… More >

T.W. Dong¹, H.S. Liu¹, S.L. Jiang², L.Gu¹, Q.W. Xiao¹, Z. Yu¹, X.F. Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.5, pp. 369-390, 2013, DOI:10.3970/cmes.2013.095.369

Abstract In this paper, we present a free surface flow model with a forced revolving moving boundary for partially filled screw extrusion. The incompressible smoothed particle hydrodynamics (ISPH) is used to simulate this complex flow. A set of organic glass experimental device for this partially filled fluid is manufactured. SPH results are satisfactorily compared with experiment results. The computed free surfaces are in good agreement with the free surfaces obtained from the experiment. Further analysis shows that with the increase of the speed, the average velocity of fluid increases, the effect of centrifugal force begin to show up, the maximum pressure… More >