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《中国航空学报》1990,(1)
A new algorithm for ray tracing bicubic Bezier surface intersection is presented. In order to find the intersected patches more effectively, a quadtree representation for surface patches is utilized. The introduction of the alternative binary tree subdivision of Bezier surface effectively improves the performance of the ray surface intersection, with the benefit of avoiding the problem that the binary tree subdivision would produce long narrow patches and speeding the intersection finding process. The algorithm has been programmed in FORTRAN-77 and on prime-550 II computer. The result shows that its structure is simple and it is easy to implement with good performance. 相似文献
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《中国航空学报》1990,(1)
F luid MeehanieSI沈veloPment of a Seeond〔记neration Injeetor Driven Transonie Wind Tunnel at BUAA .........................……Ling YunPei,Zhang Hua and Liu Jian(Bg)Analysis of Leakage厂haracteristies of Labyrinth Seals··……Zhu Yizheng and He Feng(B15)on the Aeeelerating Airflow Problem in the Test Seetion of a Transonie Wind Tunnel·....·.····.........……,·.一.·................……乙eng Guofeng(B73)Aerodynamie Analysis and Modifieation氏sign of NPU Airfoils .. ..… 相似文献
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As the low temperature non-equilibrium plasma, microwave plasma has the same effects with the plasma produced by the traditional high voltage electrode, which has the function of widening ignition boundary and improving combustion. Microwave has the advantages of uniformity, particle selectivity and no electrode. It can generate a large range of non-equilibrium plasma with relatively low power without electrode ablation. Therefore, how to maximize its effectiveness has become the research hotspo... 相似文献
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飞机整体壁板广义槽分层识别方法及其实现算法(英文) 总被引：5，自引：0，他引：5
To automatically obtain a machining area in numerical control （NC） programming, a data model of generalized pocket is established by analyzing aircraft integral panel characteristics, and a feature recognition approach is proposed. First, by reference to the practical slice-machining process of an aircraft integral panel, both the part and the blank are sliced in the Z-axis direction; hence a feature profile is created according to the slicing planes and the contours are formed by the intersection of the slicing planes with the part and its blank. Second, the auxiliary features of the generalized pocket are also determined based on the face type and the position, to correct the profile of the pocket. Finally, the generalized pocket feature relationship tree is constructed by matching the vertical relationships among the features. Machining feature information produced by using this method can be directly used to calculate the cutter path. The validity and practicability of the method is verified by NC programming for aircraft panels. 相似文献
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