Parallel Computation Of Lightning Numerical Mode GPU And Its Preliminary Application

In order to improve the reliability of the numerical model of lightning,this article is based on the existing numerical simulation program,lightning by amending its air electric field calculation part of the iterative algorithm,remove the data dependency in the process of iteration and use CUDA architecture,transplanting it to the GPU parallel computing platform,make the precision of the numerical model has been speed greatly enhanced greatly.In addition,based on the newly built lightning numerical simulation program,a fixed classical charge structure was established for sensitivity experiments,and the relationship between the cloud charge structure(mainly the closest charge layer to the ground)and the characteristics of ascending lightning initiation and propagation was discussed.The main research results are as follows:(1)Based on the existing lightning numerical model,CUDA architecture is adopted to remove the dependence of the iterative algorithm in the electric field calculation,and the PGI compiler is used to rebuild and compile,so that the calculation method can be GPU-parallelized,which greatly improves the accuracy and speed of the lightning numerical simulation program,and the acceleration ratio is around 30.In addition,by comparing the different spatial resolution of two algorithms under different iterative precision of the calculation speed,found that under the same iteration precision,the higher spatial resolution,the GPU acceleration of parallel computing than the higher,the same spatial resolution,under different iterative precision parallel speedup,this with GPU multi-thread relate core features,spatial grid points,the more the more core bit used at the same time,computing speed is higher than the more.(2)Under the classical double-layer charge structure,there is a certain relationship between the self-sustaining type of negative ground flashover initiation and the charge structure.The higher the main negative charge area is,the larger the charge density and charge distribution range of the main negative area required by the self-sustaining type of negative ground flashover are.For different types of lightning initial conditions,speculated that are self sustaining type Xing Fu flash originating main negative area high threshold,when the main negative zone height is higher than the value,as the main negative charge accumulating,area will be like the lightning in the initial began in the cloud rather than on self sustaining type Xing Fu lightning,when the main negative zone height is lower than the value,the charge accumulation can cause self sustaining Xing Fu to flash originating type.(3)The propagation of the simulated self-sustaining upward negative ground flash channel has certain characteristics,which is manifested as that the lightning at the beginning of the building tip almost has no branch,and it spreads vertically.With the continuous development of lightning,the lightning gradually appears horizontal extension,and the lightning channel branches gradually increase.Branches generally develop from the bottom to the top.The development of new branches in the front part of the main channel will hinder the development of lightning branches located at the bottom to some extent,and branches located at the same height may have a trend of simultaneous development.