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基于曲率特征的三维模型对称性检测技术
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作者 王东旭 石跃祥 《现代电子技术》 2013年第8期89-92,共4页
针对三维模型上对称性提取效率不高的问题,在此提出了一种改进的对称性检测方法,该方法通过分析和计算三维模型上曲面的曲率特征,得到模型表面上凸起或者凹陷的褶皱线,再将褶皱线作为分析检测曲面对称性的依据,结合变换空间聚类的方法,... 针对三维模型上对称性提取效率不高的问题,在此提出了一种改进的对称性检测方法,该方法通过分析和计算三维模型上曲面的曲率特征,得到模型表面上凸起或者凹陷的褶皱线,再将褶皱线作为分析检测曲面对称性的依据,结合变换空间聚类的方法,计算得到模型整体的对称变换。实验结果表明,该方法通过以简单的褶皱线来描述和刻画模型上的复杂曲面,不但能够得到正确的对称变换,还能够大幅减少算法的计算量,加速提取过程。 展开更多
关键词 三维模型处理 几何建模 对称性检测 三维模型曲率特征 聚类方法
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NUMERICAL STUDY ON THE THREE-DIMENSIONAL CHARA-CTERISTICS OF THE TIDAL CURRENT AROUND HARBOR ENTRANCE 被引量:2
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作者 XIE Ming-xiao ZHANG Wei 《Journal of Hydrodynamics》 SCIE EI CSCD 2010年第6期847-855,共9页
A three-dimensional (3-D) numerical model is established to investigate the tidal current motion characteristics around the harbor entrance. Computational approaches consist of the finite difference method, time-spl... A three-dimensional (3-D) numerical model is established to investigate the tidal current motion characteristics around the harbor entrance. Computational approaches consist of the finite difference method, time-splitting technique, C-grid, and a high-order turbulence closure model. The Ocean General Circulation Model (OGCM) inundation scheme is incorporated in the model. An engineering application, Lianyungang Harbor, China, is used as a real-life case. The model is validated by showing that the simulated results agree well with the field data. In the approach channel, the tidal current shows a deflection effect especially in the bottom layer. As for Lianyungang Harbor, a jet flow forms at the tip of the northern breakwater, which drives a circulation flow at the inner side of the harbor entrance. In the vertical, the flow is significantly stratified at the entrance section within the channel, where the flow direction varies between layers and the speed distribution is quite uniform. These 3-D features become less evident to the offshore. Additionally, the sensitivity analysis shows that the flow deflection is related to the channel depth. Simulation results also imply that the siltation rate at the entrance section of the approach channel tends to be more uniform by the 3-D flow motion feature, and could be more significant with the increase of the channel depth. 展开更多
关键词 3-d model harbor entrance OGCM inundation scheme stratification features
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