Research On Numerical Simulation Of The Unsteady Flows Over Rotating Bodies

This paper focuses on the numerical simulation of the problem of unsteady flow over rotatingbodies. To simulate the unsteady flow, two methods, which are moving grids and rotating coordinatesystem, are adopted. Two sets of computational codes are developed for solving2-D Euler/N-Sunsteady flow, respectively. In this paper, the two phenomenons, which are NACA0012airfoiloscillation and rotating cylinder in viscous fluid, are studied in CFD by the method of dualtime-stepping. First, to study the unsteady flow, the steady flow computational codes are made withEuler/N-S equations, and the steady flow are simulated by the steady flow computational codes. Thecomputational codes are developed for solving2-D steady Euler/N-S equation, which applyJameson’s finite-volume method and four-stages Runge-Kutta time-stepping scheme. S-Aone-equation model is adopted for considering the effects of turbulence. Then, based on the developedcodes, the unsteady flows over rotating bodies are investigated, which means the codes are developedfrom steady flow to unsteady flow by the methods of moving grids and rotating coordinate system.Two methods both have advantages, and simulate the unsteady flow successfully.Moving grids can solve the moving of boundary and the morph of boundary effectively. In thispaper, the rotating monving is the moving of boundary, so the moving grids are adopted. The entiregrid points update together with the boundary rotation. In this method, we simulate inviscous/viscousflows over oscillating NACA0012airfoil and viscous flows over rotating cylinder, the result issatisfied.Rotating coordinate system has advantages dealing with flow past rotating bodies. While thecoordinate system is attached to the solid object, the grid points are relatively static to the rotatingbodies, that means the mesh is static. In this method, we simulate inviscous/viscous flow pastoscillating NACA0012airfoil and viscous flows past rotation cylinder. The results prove thefeasibility of the rotating coordinate system processing rotation issues.