The radial point interpolation method (RPIM) is combined with the appropriate implicit time integration technique for transient wave propagation analysis in this work. The dispersion error issue of the numerical results is investigated detailedly by performing the dispersion analysis. It is found that the RPIM with sufficiently large support domains of quadrature points is able to yield almost no spatial dispersion errors which are much lower than those from the traditional finite element (FE) approach with the identical node distributions, hence we can monotonically improve the computation accuracy of the numerical results by using the decreasing time steps, namely the present method shows the important and attractive monotonic convergence property for transient wave analysis. This property makes the present method clearly superior to the standard FE approach in transient wave analysis and much more accurate solutions can be achieved. Several typical benchmark problems of transient wave propagations are studied to assess the robust and superior performance of the present method over the conventional FE for transient wave analysis. 

Performance of the radial point interpolation method (RPIM) with implicit time integration scheme for transient wave propagation dynamics

Smoothed finite element method (S-FEM) has attracted lots of attentions in the fields of computational mechanics, especially in solid mechanics and heat transfer problems. In computational fluid dynamics, works on S-FEM were limited to two-dimensional problems. This work aims to extend the S-FEM to three-dimensional (3D) incompressible laminar flows. Wedge element grids and grids with mixed wedge and hexahedral elements are formulated for 3D incompressible laminar flows based on the cell-based S-FEM (CS-FEM). To reduce numerical oscillations, we implemented the streamline-upwind/Petrov-Galerkin method (SUPG) together with the stabilized pressure gradient projection (SPGP). Several examples are presented, including the Beltrami flow, lid-driven cavity flow, backward facing step flow and microchannel flow, to validate and examine the presented method. The results indicate that wedge elements and mixed wedge-hexahedral elements based on the CS-FEM have higher computational efficiency than that of hexahedral elements based on the CS-FEM for the same level of computational accuracy. It is also found that the present CS-FEM performed better than the standard FEM in dealing with pressure stability. The flow characteristics are well captured by the CS-FEM using the mixed wedge-hexahedral elements, and the numerical results are acceptable compared to those of STAR-CCM+.

A cell-based smoothed finite element method (CS-FEM) for three-dimensional incompressible laminar flows using mixed wedge-hexahedral element

In this paper, a novel enriched three-node triangular element with the augmented interpolation cover functions is proposed based on the original linear triangular element for two-dimensional solids. In this enriched triangular element, the augmented interpolation cover functions are employed to enrich the original standard linear shape functions over element patches. As a result, the original linear approximation space can be effectively enriched without adding extra nodes. To eliminate the linear dependence issue of the present method, an effective scheme is used to make the system matrices of the numerical model completely positive-definite. Through several typical numerical examples, the abilities of the present enriched three node triangular element in forced and free vibration analysis of two-dimensional solids are studied. The results show that, compared with the original linear triangular element, the present element can not only provide more accurate numerical results, but also have higher computational efficiency and convergence rate.

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Free and Forced Vibration Analysis of Two-Dimensional Linear Elastic Solids Using the Finite Element Methods Enriched by Interpolation Cover Functions

Effect of the ballast height on the slipstream and wake flow of high-speed train

Numerical computation of multi-phase flows

In this paper, the exhaustive usage and implementation of Streamline-Upwind/Petrov-Galerkin method combining with Stabilized Pressure Gradient Projection (SUPG/SPGP) for incompressible Navier-Stokes equations are investigated. We validate and explore the behavior of cell-based smoothed finite element method (CS-FEM) and finite element method (FEM) based on SUPG/SPGP on five numerical examples. First, the Taylor-Green vortex example shows that CS-FEM based on SUPG/SPGP (CSFEM-SUPG/SPGP) are more accurate and has better robustness against distorted mesh than that of FEM based on SUPG/SPGP (FEM-SUPG/SPGP). Moreover, the wider range of SPGP stability parameter for CS-FEM-SUPG/SPGP is found in the condition of maintaining accurate result. Meanwhile, the lid-driven cavity flow example shows that the SUPG/SPGP method is favorable for incompressible flow at relatively high Reynolds number. The other numerical examples show good performances of the proposed method on the unsteady flows and micro-channel flow. In summary, proposed CS-FEM-SUPG/SPGP shows good performances on obtaining accurate results.

A cell-based smoothed finite element method stabilized by implicit SUPG/SPGP/Fractional step method for incompressible flow

Numerical study of snow accumulation on the bogies of a high-speed train using URANS coupled with discrete phase model

A numerical study on water spray from wheel of high-speed train

A numerical simulation method based on the improved delayed detached eddy simulation coupled with a discrete phase model is used to study the influence of the snow on the performance of bogies of a...

A numerical study of snow accumulation on the bogies of high-speed trains based on coupling improved delayed detached eddy simulation and discrete phase model:

Mingyang Liu

Papers

A cell-based smoothed finite element method (CS-FEM) for three-dimensional incompressible laminar flows using mixed wedge-hexahedral element

A cell-based smoothed finite element method stabilized by implicit SUPG/SPGP/Fractional step method for incompressible flow

Numerical study of snow accumulation on the bogies of a high-speed train using URANS coupled with discrete phase model

A numerical study on water spray from wheel of high-speed train

A numerical study of snow accumulation on the bogies of high-speed trains based on coupling improved delayed detached eddy simulation and discrete phase model: