基于笛卡儿网格的自动化CFD特点分析及一种新策略

Characteristics Analysis of Automated CFD Based on Cartesian Grid and a New Strategy

计算流体力学(CFD)计算通常分为预处理、求解和后处理三个独立的过程,其中预处理过程需耗费的人力时间占整个计算周期人力时间的70%以上。CFD计算自动化,尤其是网格生成自动化,对于提升气动计算效率具有重要意义。当前,对于无黏Euler方程的求解,国内外已出现较为成熟的自动化CFD商业软件,如Cart3D、KARALIT CFD、PiFlow等。上述软件通常采用笛卡儿网格技术自动生成网格,采用单元切割或浸入边界法处理物面边界。在文献调研的基础上,本文对基于笛卡儿网格的自动化CFD软件功能与特点进行了总结分析。在此基础上,对笛卡儿网格框架下自动化CFD技术路线的优缺点进行了分析,提炼了该技术路线存在的问题。最后,介绍了一种基于非结构有限差分法的自动化CFD新框架和初步实现方法,探索自动化CFD发展的新路径。

CFD computational process is usually divided into three independent parts:pre-preprocessing,solving and post-processing.The labor time consumed by the per-preprocessing accounts for more than 70%of the whole computation cycle.The automation of CFD computation,especially the automation of grid generation,plays an important role in improving the efficiency of aerodynamic computation.At present,mature commercial automated CFD software for solving Euler equations without viscosity has appeared at home and abroad,such as Cart3D,KARALIT CFD,PiFlow,etc.The above software usually uses Cartesian grid technology to automatically generate mesh,and uses element cutting or immersion boundary method to deal with object surface boundary.On the basis of literature research,this paper summarizes and analyzes the functions and characteristics of automated CFD software based on Cartesian grid.On this basis,the advantages and disadvantages of the automated CFD technical route under the Cartesian grid framework are analyzed,and the existing problems of this technical route are refined.Finally,a new framework and a preliminary implementation method of automated CFD based on unstructured finite difference method are introduced,and a new development path of automated CFD is explored.