Modeling And Simulation Of Infrared Cumulus Cloud Based On Physical Process

Real cloud simulation is one of the important topics in the field of computer simulation,and the real-time simulation of clouds in infrared aerial scenes is of great significance to the military field.However,the density,temperature,and physical state of particles in the cloud undergo complex motion changes,which requires that the simulation model can accurately describe and efficiently calculate the cloud.There are two aspects to accurately describe the changes of the cloud,the three-dimensional physical model and the real lighting model.Efficient calculations need to ensure that the cloud simulation process is real-time so that the simulation results can support control and interaction.Aiming at the above problems,this paper models the cumulus cloud through hydrodynamic modeling and simplified multiple scattering model,and accelerates the calculation through the graphics rendering equipment,and finally completes the simulation study of infrared cumulus clouds.This paper first uses fluid dynamics to three-dimensionally model the cumulus.Based on the Navier-Stokes equation,the three-dimensional simulation area of the cloud is divided into a uniform grid.Processes like water vapor transport and phase change in the grid are calculated.Then,the distributions of cloud droplet density,water vapor density,temperature and other characteristics are obtained,and the results are stored in a three-dimensional texture.The complex calculation in the process is performed step by step by the compute shader supported by the underlying rendering tool,so as to use the parallel computing ability of GPU to improve the calculation efficiency.The calculation results are volume-rendered in the fragment shader using a ray-casting algorithm to achieve 3D rendering.Secondly,this paper uses the simplified multiple scattering model to classify and calculate the lighting phenomenon existing in the visible light model of the cumulus.After analyzing the scattering phase function and basic scattering theory,the calculation processes of transmission,single scattering,double scattering,and multiple scattering are proposed.The calculation processes is embedded into the volume rendering process through a pre-designed light integration path,and the lighting of the cloud is rendered in real time during the simulation process.Finally,this paper modified the visible light illumination model of the cloud by infrared simulation theory of the cloud,and designed the calculation process and simulation scheme of spontaneous radiation in different wavebands to obtain an infrared illumination model of the cumulus.Moreover,for the problem that the grid-based simulation method is difficult to achieve the effect of the target penetrating through clouds,a feasible simulation scheme is provided.After each chapter,the time domain and spatial domain simulation results of each model are shown and analyzed in turn.