Visualization Study And Implementation Of Aircraft Icing Based On NNWICE

Aircraft icing simulation software uses Computational Fluid Dynamics(CFD)to simulate aircraft icing phenomena under different climatic conditions,evaluating the impact on flight,which is a key tool in the aviation field.At present,the mainstream icing simulation software is mainly developed abroad.NNWICE,developed under the National Numerical Windtunnel(NNW)project,is a domestically produced,high-precision aircraft icing numerical simulation software.After the core solver module completes the numerical calculations,it is necessary to visualize the calculation results for researchers to intuitively observe the data.Visualization of aircraft icing not only needs to focus on the shape of the ice,but also should distinguish different types of icing in visual effects.To this end,based on the CFD calculation result data of NNWICE,this thesis introduces physics-based rendering technology to realize the realistic visualization of different aircraft icing materials.The main work completed in this thesis includes:(1)Analyzing the visual characteristics of different types of icing,conducting research on related graphics technology,summarizing the advantages and disadvantages of NNWICE’s existing visualization algorithms,determining the specific visual effects to be achieved for realistic visualization of icing simulation software,and providing theoretical support for the subsequent research of this thesis.(2)Researching and designing a realistic lighting model suitable for aircraft icing materials.A frost ice rendering model is proposed,which uses a subsurface scattering approximation method to improve the Cook-Torrance BRDF,achieving the rendering of semi-transparent frost ice.The rendering of clear ice uses the current algorithm of NNWICE.Further,by interpolating and blending the frost ice model and clear ice model,the rendering of mixed ice with different transparencies is realized.Then an experiment is designed to verify the actual effect of the lighting model in this thesis.The model in this thesis is implemented in an open-source offline renderer,and the rendering of different types of aircraft icing materials is conducted by changing parameters.The experimental results show that the model in this thesis can complete the rendering of various types of aircraft icing materials.(3)Combining NNWICE’s existing visualization rendering algorithms,the model in this thesis is implemented in the Open GL rendering pipeline.In order to implement subsurface scattering approximation in NNWICE,a method to obtain a local thickness map in screen space is proposed.The effects in real-time rendering are demonstrated,and rendering speed tests are carried out.The results verify that the method in this thesis can meet the speed of real-time rendering and perform realistic rendering of aircraft icing.Through the above work,this thesis proposes a lighting model that can describe various types of aircraft icing materials,and provides a real-time rendering implementation scheme based on Open GL,providing theoretical support and practical experience for the visualization of domestically produced aircraft icing simulation software.