Non-structured Grid In The Low Resistance Shape Design Of Transonic

Unstructured grid methodology has demonstrated considerable success in computational fluid dynamics (CFD) mainly due to its inherent flexibility for discretization of geometrically complex domains.In this thesis, the advancing-front method is used to generate three-dimensional unstructured grid. In order to improve the quality of grid, new rule to choice grid vertex and grid optimization technique are used. Based on the unstructured grid, Euler equations are solved using the cell-centered finite volume spatial discretization and four-stage Runge-Kutta time-stepping scheme with standard convergence acceleration techniques such as local time stepping and implicit residual smoothing.In order to reduce the wave drag of the transonic and supersonic aircraft, this thesis presents an optimization way for the equivalent circle shape of the aircraft under the assumption of the area law. Using the Euler equations as the calculation model, and the grades optimization as the optimization model, directing the specialty of the equivalent rotator shape of the aircraft, this thesis presents a way to form the shape and makes the variables less and the speed of the calculation more rapid.As the tradition method can only estimate the addition of wave drag from subsonic to supersonic, and can not calculate the change of drag when Mach number increases. The method of this thesis can simulate the subsonic, transonic and supersonic flow around the equivalent rotator shape, and without the limit of Mach number. So present method can capture the shock of all kinds of equivalent rotator shape, and can design low wave drag configuration.