Investigation On Pre-Processing System For 3D Finite Difference Method In Explosion Problems

The establishment of the computational model and the division of the computational grid are fundamental to the numerical simulation of the explosion.The feasibility and reliability of the numerical simulation depends on the correctness of the model and the quality of the grid.For the finite-difference Euler solver,ExVisual,which is a self-developed explosion solving software,it is very important to improve the methods of the establishing model,generating mesh and to meet the requirements.This study includes building geometric model of pre-processor,generating finitedifference grid data and completing visualization of pre-processor with the Visualization Toolkit.The Visualization Toolkit is used to realize the visualization in the pre-processing system.Qt has a cross-platform graphical user interface application development framework to create user-friendly applications not like VTK.Then,coding the user interface with Qt and jointing the Visualization Toolkit to realize the three-dimensional model construction,meshing and displaying.The main work is shown below:1.The visualization of explosion pre-processing system.According to the demands of the 3D finite-difference pre-processing system for explosion problem,the Visualization Toolkit is used to visualize the explosion problem pre-processing system in the graphic image output interface.The formation of the geometry model and the visualization and generating the grid and the displaying of the grid and user interaction has been studied.2.Finite-difference grid generation for explosion problems.According to the characteristics of the rectangular hexahedron mesh required by the three-dimensional finitedifference solver for explosion problem,take the advantage of implicit function modeling to construct the model.The data selection function of implicit number is used to extract the data set and generate finite-difference grid data.3.The implicit function modeling and the STL file interface are used to build the model of the explosion pre-processor.Modeling algorithms are one of the most important visualization techniques.Creating or changing geometrical data or topological relationships for datasets is the property of modeling algorithms.The method of implicit function modeling is provided for 3D modeling of finite-difference pre-processing system.At the same time,the pre-processing system provides STL file interface for the rapid creation of threedimensional modeling.4.Design the interface file between the pre-processing system and the solver.Interface the data files generated by the pre-processing and the solver.The pre-processing system is applied to the 3D finite difference serial solver.Assess the effectiveness of interface files and software reliability.5.Design and development of pre-processing system based on Qt and VTK.The user interface was coded based on the graphical user interface application development framework(Qt)in C++.And the VTK was used to visualize the 3D finite difference preprocessing system.Object-oriented programming could use the properties of Qt and VTK respectively.The pre-processing system could be developed more reasonably and an add-on functions' development can be made.