Research And Application Of Flow Visualization Based On Pertinence And Geometric Shapes

This dissertation focuses on visualization of flow data which is obtained by numerical computation. On the basis of analysis on the characteristics of flow data, we use methods of scatter data visualization and 3D vector visualization to deal with flow data which is obtained by numerical computation. On the basis of analysis on the method of isoline, according to the characteristics of flow data, this dissertation use a new method to obtain isoline. In order to help researcher to know the inside law of flow data, this dissertation use a method to obtain inside data by interpolation computation. Based on the method of Marching Cubes, this dissertation make some improve on it and use it obtain Isosurface. In allusion to the vector data of flow data, this dissertation use hedgehog method to visualize it, and streamline technology is also use to obtain some law from flow data.The organization structure of full text is as follows:In chapter 1, introduce some knowledge about visualization in scientific computing, On the basis of these knowledge, Introduce visualization technology which is used in the deal with of flow data, Including the research results of this field. At last, introduce the research content and organization structure of full text.In chapter 2, in order to get flow data, introduce some knowledge about grid data, such as the type of grid, the transform of data from physics space to computation space and so on. At last, introduce the file type of flow data which is used to visualization.In chapter 3, Using isoline and nephogram technology to visualize flow data. At first, analysis the characters of isoline technology, and then according the practice, introduce a method to obtain isoline. it divide a rectangle to four triangles, and then obtain isoline from each triangle, avoids the topology disagree. In order to help researcher to know the inside law of flow data, this dissertation use a method to obtain inside data by interpolation computation.In chapter 4, Using isosurfaces technology to visualize flow datam. In order to speed the extraction of isosurfaces from flow data, a method which is based on the relativity of each cell in flow data and threshold mapping, is presented here, as well as the corresponding data structure for this method. As we know, the edge of each cell in flow data may be shared by other cells. So this characteristic can be used to avoid repeated calculation of intersection on the same edge. This dissertation presents a method which utilizes the relationship between the span of each cell and whole flow data, to speed the search of cells which is passed by isosurface.