The Research Of Parallel Computing And Visualization Of Surface Dust Evolution

With the economic development,urban environmental problems have become more and more serious.In recent years,there is serious air pollution in many cities of China has become the first carcinogenic factor of Chinese residents.Surface dust,as part of the air pollutants,causes great harm to the health of people when its concentration is too high.In addition,surface dust is also very destructive on ecological environment.The study of the evolution of dust particles has a guiding significance for the effective protection of the environment and reducing environmental pollution.In view of the fact that the study of surface dust has important theoretical significance and practical application value,taking Yanchang campus in Shanghai University as the object of study,this essay studies the surface dust evolution in campus,with the main findings as follows:(1)Wind field simulation for virtual campus model is studied.First,the simple virtual campus model is built in CFD pre-processing software GAMBIT.And the boundary is defined and the model is meshed.Then,CFD processing software FLUENT is used to simulate the distribution of wind speed on the virtual campus model.Last,CFD post-processing software Tecplot is used to get wind speed text files of virtual campus;(2)KMC-based parallel algorithm is proposed to simulate the evolution of dust particles.Kinetic Monte Carlo(KMC)method is applied in four events of dust particle simulation:dust particle evolution,sedimentation,raised,collision.Data distribution way and communication optimizing strategy are raised to balance the load of every process and reduce the communication expense among processes.By comparing the accumulated data and simulated data at eleven dust collection points,it proves the effectiveness of the algorithm.Parallel algorithm also makes up for the shortage of serial computing and makes the simulation of large-scale virtual environment possible;(3)The inverse distance hybrid interpolation algorithm is proposed to calculate the dust concentration.The dust concentration obtained by the simulation calculation is characterized by grid and discontinuity.In order to visualize the dust concentration results,an inverse distance hybrid interpolation combining the inverse distance weighted interpolation method and the Kriging interpolation algorithm is proposed.The experimental results show that the inverse distance hybrid interpolation algorithm not only has high precision,but also has high computational efficiency;(4)The pseudo-color map technique is used to visualize the surface dust density and a color-based color interpolation method is proposed.First,the three-dimensional model is constructed according to the measurement point and the value information of the dust concentration data set;then,the surface dust concentration data set and the color space model are color-mapped and three-dimensional spatial hierarchical model is divided.The three-dimensional visualization of dust is carried out for each layer according to the pseudo image coding algorithm and the color clustering parameter feature;at last,according to the color progressive interpolation algorithm,the adjacent layer of the pseudo image is smoothed.The results of the cumulative visualization of the surface dust on the ground surface indicate that the pseudo-image of the surface dust concentration data set by this algorithm is strong in color rending,and color transition is smooth and the information of the visualization of surface dust concentration is expressed;(5)The surface dust visualization simulation method is proposed based on OpenGL.Visual C++ is used as the software platform.The idea of particle system is applied to take surface dust as a particle set,in which randomly distributed particles are in KMC motion.The interactive visualized control of dust evolution simulation system is also realized.The main innovations of this paper include:(1)The dust particle evolution is divided into four types of events:diffusion,sedimentation,uplift and collision.The parallel simulation model of surface dust KMC evolution is established,and the validity of the simulation model of surface dust evolution is verified by comparison with the experimental data;(2)The inverse distance hybrid interpolation algorithm is proposed to interpolate the concentration of surface dust,which ensures the accuracy of the interpolation algorithm and improves operational efficiency at the same time;(3)Using the pseudo-color map technique,a color-based color interpolation method is proposed to visualize the surface dust concentration and enhance the rending effect.