N. Thai-Quang¹, N. Mai-Duy¹, C.-D. Tran¹, T. Tran-Cong^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.1, pp. 49-90, 2013, DOI:10.3970/cmes.2013.096.049

Abstract In this paper, we present a numerical scheme, based on the direct forcing immersed boundary (DFIB) approach and compact integrated radial basis function (CIRBF) approximations, for solving the Navier-Stokes equations in two dimensions. The problem domain of complicated shape is embedded in a Cartesian grid containing Eulerian nodes. Non-slip conditions on the inner boundaries, represented by Lagrangian nodes, are imposed by means of the DFIB method, in which a smoothed version of the discrete delta functions is utilised to transfer the physical quantities between two types of nodes. The velocities and pressure variables are approximated locally on Eulerian nodes using… More >

Qiang Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.3, pp. 207-224, 2013, DOI:10.32604/cmes.2013.094.207

Abstract In this paper, an immersed boundary method (IBM) has been developed to simulate three-dimensional (3D) complex flows in the injection molding process, in which the irregular boundary of mould is treated by a level set function. The melt front (melt-air interface) is captured and treated using the coupled level set and volume of fluid (CLSVOF) method. The finite volume method on the nonstaggered meshes is implemented to solve the governing equations, and the melt filling process is simulated in a rectangular mould with both thick- and thin-wall sections. The numerical result shows good agreement with the available data. Finally, the… More >

F.P. Mariano¹, L.Q. Moreira¹, A. Silveira-Neto¹, C.B. da Silva², J.C.F. Pereira²

CMES-Computer Modeling in Engineering & Sciences, Vol.59, No.2, pp. 181-216, 2010, DOI:10.3970/cmes.2010.059.181

Abstract A new numerical methodology combining Fourier pseudo-spectral and immersed boundary methods - IMERSPEC - is developed for fluid flow problems governed by the incompressible Navier-Stokes equations. The numerical algorithm consists in a classical Fourier pseudo-spectral methodology using the collocation method where wall boundary conditions are modelled by using an immersed boundary method (IBM). The performance of that new methodology is exemplified in two-dimensional numerical simulations of Green-Taylor decaying vortex, lid-driven cavity and flow over a square cylinder. The convergence rate, the accuracy, the influence of the Reynolds number and the external domain size are analyzed. This new method combines some… More >

A.R. da Silva¹, A. Silveira-Neto^2,3, D.A. Rade^2,4, R.Francis⁴, E.A. Santos⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.3, pp. 285-304, 2009, DOI:10.3970/cmes.2009.050.285

Abstract In the context of computational fluid dynamics a numerical investigation of incompressible flow around fixed pairs of rigid circular cylinders was carried out. The two-dimensional filtered Navier-Stokes equations with the Smagorinsky sub-grid scale model were solved using a Cartesian non-uniform grid. The immersed Boundary Method with the Virtual Physical Model was used in order to model the presence of two circular cylinders embedded in the flow. The fractional time step method was used to couple pressure and velocity fields. The simulations were carried out for Reynolds number equal to 72,000 for pitch ratio equal to 2 and different arrangements regarding… More >

A. Mark^1,2, R. Rundqvist¹, F. Edelvik¹

FDMP-Fluid Dynamics & Materials Processing, Vol.7, No.3, pp. 241-258, 2011, DOI:10.3970/fdmp.2011.007.241

Abstract In the literature immersed boundary methods are employed to simulate complex flows around moving arbitrary bodies without the necessity of remeshing. These methods employ a regular Eulerian mesh to simulate the fluid flow and a Lagrangian representation of the boundary of the bodies. The two representations can be coupled through an immersed boundary condition constraining the fluid to exactly follow the boundary of the bodies (immersed boundaries). Typically such methods suffer from accuracy problems, that arise from spurious mass fluxes over the immersed boundary (IB), pressure boundary conditions or high density ratios. The mirroring IB method Mark (2008); Mark and… More >

Cheng-Hsiu Yang¹, Cheng Chang¹, Chao-An Lin^1,2

CMC-Computers, Materials & Continua, Vol.11, No.3, pp. 209-228, 2009, DOI:10.3970/cmc.2009.011.209

Abstract In the present study, a lattice Boltzmann method based new immersed boundary technique is proposed for simulating two-dimensional viscous incompressible flows interacting with stationary and moving solid boundaries. The lattice Boltzmann method with known force field is used to simulate the flow where the complex geometry is immersed inside the computational domain. This is achieved via direct-momentum forcing on a Cartesian grid by combining "solid-body forcing" at solid nodes and interpolation on neighboring fluid nodes. The proposed method is examined by simulating decaying vortex, 2D flow over an asymmetrically placed cylinder, and in-line oscillating cylinder in a fluid at rest.… More >