三维球壳地幔流动形式探讨

建立三维球壳模型，将地壳和地幔作为不可压缩牛顿粘性流体处理，考虑了大陆、大洋、洋脊及俯冲带的不同物性参数，利用有限元法求解流体运动的基本方程组，研究地幔流动、板块运动与大地构造之间的关系。计算表明，速度边界条件、粘度分布等是影响地幔流动形式的主要因素。若地表径向取应力边界条件，且径向速度自由，则没有封闭的对流环存在。计算得到的地表径向速度分布与全球的构造分区具有显著的对应关系：在岛弧区、造山区速度向上运动，在大洋区、边缘海及裂谷区速度向下运动。

THE PATTERNS OF MANTLE FLOW IN 3-D SPHERICAL SHELL MODELS

In the paper, 3-D spherical shell models are presented to study the relationship between mantle flow and plates' movements and factors that influence the patterns of mantle flow. Incompressible, newtonian fluid medium is used to simulate the mantle and crust. The basic equations are solved by finite element method with a punitive factor. The results show that velocity boundary condition and viscosity are the main factors that influence mantle flow patterns. If the radial velocity boundary at the earth surface is taken to be free, no closed convection cells appear and mantle flow correlates well with the global tectogenesis.