Numerically analyzing more efficiently high-lift aerodynamics of transport aircraft with omni-tree cartesian grids

Aim: Refs. 1, 2 and 3 are recent developments dealing with transport aircraft high-lift aerodynamics. Different from them, we use omni-tree Cartesian grids to achieve higher efficiency. In this paper, the computation of complex flow field using the adaptive Cartesian grid method and the cell-center finite volume method is carried out and compared with wind-tunnel experiments. We mainly use the omni-tree data structure and the face-to-face algorithm. The omni-tree structure allows the Cartesian grid to be adapted in an arbitrary manner and offers the potential of dramatic reduction of total number of cells to achieve a given level of solution accuracy. The face-to-face algorithm is established to precisely conduct the information exchange of flow fields on the interfaces among different zones. We solve the Euler equations using the cell-centered finite volume method and the dual-time step-length scheme. The above algorithm and methods have been verified with two test cases involving respectively a takeoff configuration and a landing one. Some computation results, given in Figs. 3 and 4, show preliminarily that the grid generation and the flow field calculation are accurate; other computation results, presented in Tables 1 and 2, indicate preliminarily that the total number of cells are dramatically reduced with the accuracy almost unaffected. Thus we conclude preliminarily that our algorithm and methods are more efficient for solving the flow field of the complex high-lift configuration.