将计算机图形学领域的粒子系统引入数字流域研究,研发了基于通用网格的水沙模拟时空过程三维可视化系统。该系统建立数据结构描述粒子信息和计算或者虚拟网格单元信息传递关系;采用网格控制粒子随机生成;提出局部搜索定位方法来快速确定粒子位置;通过反距离加权平方插值提取水流信息;利用自适应龙格-库塔方法实现粒子的动态变化;设计了附有更多水流属性的水体粒子;研究了流场变化过程中粒子分布不均的问题。将上述方法应用于三峡与葛洲坝间河道水流的动态可视化模拟,验证了该系统的有效性和实用性。
Based on a common grid and introducing the particle systems from the field of computer graphics,the paper presents a new method for visualizing the dynamic behavior of simulated water and sediment movements in digital river basin.Some of the key techniques involved in the development of the method are discussed in detail.These techniques are the data structure design for storing particle and grid cell information,the random generation of a particle that is controlled by the computational grid,the local searching and positioning of the particle,the flow field conversion from Euler representation to Lagrange representation using the self-adaptive Runge-Kutta method,and the design of particle shapes with water and sediment information.The issue of the uneven distribution of particles during the course of flow field change has been solved.The new method is tested and applied in the flow visualization system developed for the Yangtze River reach between Three Gorges and Gezhouba.