共形FDTD网格剖分方法及其在舰船电磁环境效应仿真中的应用
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摘要
对于时域有限差分(FDTD)数值仿真方法,网格生成是其重要前处理过程。大部分商业模型都使用三角形面片描述其结构,而FDTD必须使用六面体网格,因此必须使用合适的剖分算法将模型结构对齐到FDTD的计算区域。而目前基于原点探测的传统网格生成算法存在效率和精度等若干问题。基于射线追踪原理,通过检测网格射线族和三角形面片模型间的交点位置,求解模型结构和FDTD元胞之间的位置关系,从而可高效、精确生成FDTD仿真算法必须的网格信息,并通过进一步应用多方向射线追踪方法,解决特殊模型结构可能导致部分模型的剖分信息不完整的问题。最后,通过将该剖分方法应用于带有战斗机的航母飞行甲板模型,并结合高阶共形FDTD方法,成功预测其在高功率电磁脉冲下的表面电流分布问题。
Mesh generation is an important pre-process for the finite difference time domain(FDTD)simu-lation algorithm. Most commercial softwares use triangle pieces to describe model geometry,while theFDTD algorithm must use rectangular cells to achieve the same end;thus,a meshing process is requiredin order to snip the original model into its FDTD computational region. The traditional origin-searchingbased meshing technique is low in both efficiency and accuracy. In this article,we detect the interceptionpoint between the model and the FDTD grid ray clusters based on the ray tracing technique,which generatesthe mesh information with high accuracy and efficiency. Furthermore,the multiple direction ray tracingtechnique is used in order to correctly capture the mesh for some special models. Finally,we apply the proposedmethod,combined with high-order conformal FDTD simulation algorithm,on an ship platform with aircrafts,whose surface current distribution under a high power EMP incident wave is successfully simulated.
Mesh generation is an important pre-process for the finite difference time domain(FDTD)simu-lation algorithm. Most commercial softwares use triangle pieces to describe model geometry,while theFDTD algorithm must use rectangular cells to achieve the same end;thus,a meshing process is requiredin order to snip the original model into its FDTD computational region. The traditional origin-searchingbased meshing technique is low in both efficiency and accuracy. In this article,we detect the interceptionpoint between the model and the FDTD grid ray clusters based on the ray tracing technique,which generatesthe mesh information with high accuracy and efficiency. Furthermore,the multiple direction ray tracingtechnique is used in order to correctly capture the mesh for some special models. Finally,we apply the proposedmethod,combined with high-order conformal FDTD simulation algorithm,on an ship platform with aircrafts,whose surface current distribution under a high power EMP incident wave is successfully simulated.
引文
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[7]YANG J,SU D L,ZHAO X Y.The study and realization of automatic mesh generation based on electromagnetic simulation of FDTD[C]//IEEE International Symposium on Microwave,Antenna,Propagation and EMC Technologies for Wireless Communications 2009.Beijing,2009:1242-1245.
[8]SHA W,WU X L,HUANG Z X,et al.A new conformal FDTD(2,4)scheme for modeling three-dimensional curved perfectly conducting objects[J].IEEE Microwave and Wireless Components Letters,2008,18(3):149,151.
[9]WANG J,YIN W Y.Development of a novel FDTD(2,4)-compatible conformal scheme for electromagnetic computations of complex curved PEC objects[J].IEEE Transactions on Antennas and Propagation,2013,61(1):299-309.
[10]YUAN X,YIN W Y,WANG X H,et al.Optimized conformal FDTD(2,4)method for calculating reflected and diffracted electromagnetic fields of perfectly conducting wedges[J].IEEE Transactions on Electromagnetic Compatibility,2014,56(2):466-474.
[11]WALDSCHMIDT G,TAFLOVE A.Three-dimensional CAD-based mesh generator for the dey-mittra conformal FDTD algorithm[J].IEEE Transactions on Antennas and Propagation,2004,52(7):1658-1664.
[12]BENKLR S,CHAVANNES N,KUSTER N.Mastering conformal meshing for complex CAD-based C-FDTD simulations[J].IEEE Antennas and Propagation Magazine,2008,50(2):45-57.
[13]VACCARI A,CALA'LESINA A,CRISTOFORETTI L,et al.Parallel implementation of a 3D subgridding FDTD algorithm for large simulations[J].Progress in Electromagnetics Research(PIER),2011,120:263-292.
[2]HADI M F,MAHMOUD S F.Optimizing the compact-FDTD algorithm for electrically large waveguiding structures[J].Progress in Electromagnetics Research(PIER),2007,75:253-269.
[3]XIONG R B,CHEN J J,HAN Y Y,et al.Transient resistance analysis of large grounding systems using the FDTD method[J].Progress in Electromagnetics Research(PIER),2012,132:159-175.
[4]YANG M,CHEN Y.Auto Mesh:an automatically adjustable,nonuniform,orthogonal FDTD mesh generator[J].IEEE Antennas and Propagation Magazine,1999,41(2):13-19.
[5]HILL J.Efficient implementation of mesh generation and FDTD simulation of electromagnetic fields[D].Worcester:Worcester Polytechnic Institute,1996.
[6]ZHU H,GAO C,CHEN H L,et al.The research on FDTD mesh generation and visualization technology[C]//Asia-Pacific Conference on Environmental Electromagnetics(CEEM).Beijing,2012:282-284.
[7]YANG J,SU D L,ZHAO X Y.The study and realization of automatic mesh generation based on electromagnetic simulation of FDTD[C]//IEEE International Symposium on Microwave,Antenna,Propagation and EMC Technologies for Wireless Communications 2009.Beijing,2009:1242-1245.
[8]SHA W,WU X L,HUANG Z X,et al.A new conformal FDTD(2,4)scheme for modeling three-dimensional curved perfectly conducting objects[J].IEEE Microwave and Wireless Components Letters,2008,18(3):149,151.
[9]WANG J,YIN W Y.Development of a novel FDTD(2,4)-compatible conformal scheme for electromagnetic computations of complex curved PEC objects[J].IEEE Transactions on Antennas and Propagation,2013,61(1):299-309.
[10]YUAN X,YIN W Y,WANG X H,et al.Optimized conformal FDTD(2,4)method for calculating reflected and diffracted electromagnetic fields of perfectly conducting wedges[J].IEEE Transactions on Electromagnetic Compatibility,2014,56(2):466-474.
[11]WALDSCHMIDT G,TAFLOVE A.Three-dimensional CAD-based mesh generator for the dey-mittra conformal FDTD algorithm[J].IEEE Transactions on Antennas and Propagation,2004,52(7):1658-1664.
[12]BENKLR S,CHAVANNES N,KUSTER N.Mastering conformal meshing for complex CAD-based C-FDTD simulations[J].IEEE Antennas and Propagation Magazine,2008,50(2):45-57.
[13]VACCARI A,CALA'LESINA A,CRISTOFORETTI L,et al.Parallel implementation of a 3D subgridding FDTD algorithm for large simulations[J].Progress in Electromagnetics Research(PIER),2011,120:263-292.