【摘要】 建立了一种基于Delaunay背景网格插值方法和局部网格重构方法相结合的变形体动态混合网格生成方法。首先利用作者发展的定态混合网格生成技术生成变形体初始网格,即变形体附近利用结构化的四边形网格,外场采用自适应Cartesian网格,中间由三角形网格过渡。当物体运动或变形时,首先利用Liu和Qin提出的基于Delaunay背景网格的插值方法对变形体附近的网格进行变形;当物体运动或变形位移很大导致局部网格质量急剧下降、甚至网格相交时,则在局部重新生成网格。利用该方法生成了多种变形体外形的动态混合网格,如单个鱼体、双鱼串列巡游,昆虫单翼、双翼扑动,多段翼型变形等,并在鱼体巡游的非定常数值模拟中得到了应用。更多还原

【Abstract】 A hybrid dynamic grid generation technique for morphing bodies is presented based on Delaunay graph and local remeshing techniques.The initial stationary grids are generated firstly by the hybrid grid generator developed by the authors,in which structured body-fitted quadrilateral grids cover the domain close to the morphing bodies,adaptive Cartesian grids cover the outer computational domain and triangular grids fill up the gap between quads and triangles.With morphing of bodies,the grids close the bodies are firstly deformed with the technique of Delaunay graph proposed by Liu and Qin.If the quality of deformed grids are not satisfied the criterion or even crossing with each other,grid-remeshing is carried out locally.Hybrid dynamic grids over several morphing configurations are generated to validate the robustness of present grid generator,including a swimming fish,a pitching NACA0012 airfoil,a three-element airfoil with rotating flap,two swimming fishes,one and two clap and fling wings.Finally,coupled with the solver for unsteady incompressible flows,the hybrid dynamic grids are applied to simulating the unsteady flows over a swimming fish with different phase speeds,which demonstrates further the capability of numerical simulations for morphing aircrafts and unsteady Bio-fluid dynamics.更多还原