Abstract: An adaptive octree Cartesian mesh approach is presented to generate grids for computation of the complex flow field. In this grid method, based on the original Cartesian mesh approach, a surface judging relation is presented to calculate the volume of 3D cut cell since it is difficult to calculate the outward normal. Results show that this method can indeed compute the volume precisely and greatly improve accuracy of simulation of the flow field. Additionally, the new organized data structure, based on the octree method, can decrease the volume of the time to generate the grid. Furthermore, to predict the flow field, Jameson's finite volume method with the central difference scheme is used to develop an Euler solver. In this solver, since an algorithm, looping with the faces, is used in the computation of the numerical flux, the efficiency of the computation is well improved. Numerical simulations of multi-store, wing-body combination and whole aircraft complex configurations, good agreement with the experimental data are obtained. It verifies the validity of the method presented in this paper.

Key words: octr ee st ructure, cartesian g r id, adaptive r efinement, finite vo lume