Papers by Keyword: Hexahedral Mesh

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Authors: Wen Pu Zhao, Qing Yun Zhao, Zhi Qiang Lu, Shi Hua Yu
Abstract: According to the geometric characteristics of concrete box girder structure, the author proposed a way to automatically complete the concrete box girder with automatic hexahedral mesh subdivision algorithm-the vertical section method. After introducing its computing ideas, it will be applied to engineering examples to verify its feasibility.
Authors: R. Thundil Karuppa Raj, M.P. Dhyan Shankar
Abstract: Diffusing ducts are used in fluid flow systems, mainly in aeroplane engine inlets to decelerate the flow and to correspondingly increase the static pressure. The main problem in achieving a high pressure recovery is the flow separation which results in non-uniform distribution and excessive losses. The present work is aimed to study the flow characteristics in Y-shaped diffusing ducts. The Y-shaped diffuser has rectangular inlets and the outlet is circular with a certain settling length for the flow to be stabilized. The diffuser is modeled in CATIA V5 and further discretized using ICEMCFD12.1. Hexahedral mesh is generated for all diffuser cases, which have been used to capture the hydrodynamic boundary layers. ANSYS CFX 12.1 based on finite volume technique, using k-ε turbulence model is adopted for predicting the flow. The flow field through the 3-dimensional domain is captured by solving the appropriate governing equations namely, the continuity equation and the momentum equation. The convergence criterion is set to 10E-06 for mass and momentum. The whole investigation is done in two phases: in the first phase a commercial CFD code is validated for the results obtained for an S-shaped diffuser and in the second phase the same idea is then extended for the analysis of Y-shaped diffuser. The coefficient of static pressure, cross flow and axial flow velocity distributions are calculated based on the mass averaged quantities for the Y-shaped diffusers (30o and 40o).
Authors: Wei Bing Liu, Mamtimin Gheni, Lie Yu
Abstract: Meshing for finite element analysis accuracy plays a very important part in numerical simulation of Periodic Symmetric Struts Support (PSSS). Different accuracy can be obtained by different element sizes or types. Three element types and eight element sizes are used for comparing the accuracy of modal analysis in this paper. Comparing with the mutual relations of different accuracy, the scientific basis is provided for selecting the correct mesh size and improves the efficiency of numerical calculation in modal analysis.
Authors: Y. Motooka, So Noguchi, H. Igarashi
Abstract: We have previously proposed an automatic hexahedral mesh generator. It is necessary to understand about the quality and characteristic of the generated mesh to perform hexahedral edge finite element analysis in electromagnetic. Therefore, we have compared high-quality meshes with poor-quality meshes, and investigated about the factors that affect the accuracy and the computation time. In addition, we investigated about the effect of the templates used in the proposed method. We will conclusively apply the result to improving the automatic hexahedral mesh generator.
Authors: Xi Kang Liu, Jian Hai Zhang, Rong Gang Yin, Qiong Yang
Abstract: Abstract. In order to generate mesh for arch dam abutment slip block automatically, virtual grid method is proposed based on grid-based automatic generation algorithm. The proposed algorithm avoids generating initial grid in one time, but intersects the model with a series of plane sections firstly. Then form initial grid by using vector intersection method for adjacent sections. By modifying initial grid, a layer of mesh is formed. The algorithm proposed can better adapt to complex topography and generates hexahedral meshes for the block of arch dam abutment automatically. The method can present data for limit equilibrium analysis and numerical calculation method such as finite element method. Based on original topography and structural plane data, the automatic identification, generation and meshing of arch dam abutment block is accomplished.
Authors: Zahid Ibrahim Al-Hashimy, Hussain H. Al-Kayiem, Mohammad Shakir Nasif, Abdalellah. O. Mohmmed
Abstract: Slug flow regime in two and multi-phase flow in pipes is a complicated flow phenomena representing challenge in the design of the piping system. In the present work, water/air two phase flow was modeled and simulated as 3 dimensional, transient, and incompressible flow using Volume of Fluid technique in STAR-CCM+ software. The simulation was conducted to predict and evaluate the air-water slug flow in a horizontal pipe with 0.16 m diameter and 7 m long. The superficial velocities for both phases were extracted from Baker chart slug zone. The results were validated against experimental bench marking referenced in Baker chart and the proposed VOF technique shows a good capability in simulating the development of the slug flow regime. This model could be utilized for simulation of various two phase flow regimes.
Authors: Lu Sun, Guo Qun Zhao
Abstract: Surface matching technique is a key technique in automatic generation of 3D finite element mesh. In this paper, a surface matching technique including surface-gap filling, boundary match and C-node match, is introduced. Eight types of free facet configurations and their corresponding matching rules are established. Then a combined method of priority nodes and relative position relationships for boundary match is presented, and an effective method for C-node match is given, too. The methods can achieve precise match between mesh boundaries and model boundaries, and establish reasonable geometry and topology connections of matched nodes. Several examples are provided to demonstrate the accuracy and efficiency of the algorithms presented in this paper.
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