Unstructured Moving Grid Of Non-steady Gas-based Power Calculation

In this thesis, the unstructured dynamic grid technique is investigated. Full implicit dual-time temporal derivatives and cell-center finite volume method spatial derivatives are adopted to simulate unsteady flow fields of 2-D airfoil, 3-D wing.On the generating unstructured grids, the grids for Euler equations, airfoils and wings are generated by the advancing-front method.An effective and well robust unstructured dynamic grid method is developed to solve the unsteady aerodynamic problem. On the basis of classic linear spring analogy. Several modified methods for the linear spring stiffness coefficient is introduced. These methods take into account segments, faces and bodies of the cell, In the case of not much penalty in computing, the adaptation of the dynamic unstructured mesh is greater enhanced.As the flow field solver, the central scheme is presented for solving unsteady Euler equations using the cell-center finite volume spatial discretization and four-stage Runge-Kutta stepping scheme, with standard convergence acceleration techniques such as local time stepping and implicit residual smoothing.In the paper, 2~D and 3-D unsteady flow fields are computed. The results of solving the unsteady flow fields that are in agreement with the experiments show that the unsteady flow field solver is correct and the unstructured dynamic grid technique of the dissertation is well robust. So the unsteady flow field solver can be applied to various kinds of problems with moving and deforming bodies.