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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2017, Vol. 38 ›› Issue (3): 120243-120243.doi: 10.7527/S1000-6893.2016.0135

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

A dynamic assembling method based on adaptive tree structure for hierarchical overset grids

LI Xiaodong, QU Kun, CAI Jinsheng   

  1. School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2016-03-21 Revised:2016-04-27 Online:2017-03-15 Published:2016-05-04
  • Supported by:

    National Basic Research Program of China

Abstract:

The overset or chimera grid is an effective method for large-scale numerical simulation of aerodynamic problems with complex geometry, especially those with bodies in relative motion (such as the rotorcraft, store/aircraft separation). The method of adaptive cartesian grids based on the tree structure is applied to perform fast hole cutting and donor searching in the overset grid assembly process. In this technique, the geometry is represented by adaptive cartesian grids of binary trees, and this can achieve quick locating in the hole cutting. Adaptive cartesian grids of octrees are used to decompose the flow field, making the donor searching efficient. By means of a minimal overlapping-domain approach and a hierarchical strategy for overset grids, which both employ the rule of wall distance, the efficiency and quality of overset grid assembly are improved. For dynamic problems of moving bodies, multiple binary trees and octrees are applied to decrease the redundant work of updating data in procedures of overset grid assembly, substantially reducing the time consumption. The test cases demonstrate that the technique in this paper is computationally efficient and can be successfully employed to problems of multiple moving bodies.

Key words: overset grid, binary trees, octrees, adaptive cartesian grid, dynamic grid, unsteady flow, computational fluid dynamics

CLC Number: