Dynamic Docking Grid-based Non-stationary Flow Calculation Method

In the dissertation, the patched grids which are generally used in the structured grid are introduced to generate unstructured dynamic grid which can be used to solve complex unsteady flow around rotational boundary. A technique of unstructured dynamic patched grid is developed, and some numerical simulation means to solve unsteady flow around rotational boundary are investigated.Due to the character of rotational boundary, the global field is divided into two sub-areas: rotational area and static area. The grids of sub-areas are generated separately by using advancing-front method and patch on the patched interface in each physical time step. The patching style is improved to generate a better global dynamic grid. The linear spring analogy is adopted in the rotational area, so the deformation of inflection and torsion and so on can be taken into account in the numerical simulation.The compressible unsteady Euler equations are solved using the cell-centred finite volume spatial discretization and dual-time physical temporal derivatives and four-stage Runge-kutta pseudo time-stepping scheme with standard convergence acceleration techniques such as local time stepping and implicit residual smoothing. The unstructured multigrid method is investigated to improve the efficiency of numerical calculation. The programs of multigrid generating and Euler equations solving are accomplished, and the flow around the M6 wing is simulated. The result demonstrated that the agglomeration multigrid method can accelerate the calculation effectively.Unsteady flow around pitching airfoil is simulated by improved dynamic patched grid, and good results are received. The unstructured dynamic patched grid is applied to simulate the forward flight flow of helicopter rotor for the first time in our nation. A regular surface mesh is adopted, and the calculation results are accordant to experiment data and results from references.The character of a new kind of flutter exciting system is numerically simulated detailed. Both 2D and 3D models are simulated, and the quasi-steady and unsteady results are compared. We gain the results of exciting force variation with Mach number and rotational speed of rotational cylinder. The affections to the exciting force from some parameters are also investigated, such as central angle, diameter, distance from the back edge, geometry, the length and style of the gap in the cylinder. The affection of the flutter system to wing flow field is also evaluated. Some significant rules and results are received and there are some instructional functions for engineering application.