STUDY OF UNSTEADY VISCOUS TURBULENT FLOW WITH HIGH REYNOLDS PASSING TWO CYLINDERS BY RANDOM VORTEX METHOD (RVM)

Analysis of the flow past cylindrical obstacles is one of the basic issues in fluid dynamics and is of great importance. Many surveys have been conducted as to investigate the velocity field in potential and viscous flows, as a basis for finding pressure field, and investigation of forces exerted by fluid on obstacles such as uplift and drag forces in different flow regimes. Since the nature of formation of vortexes behind the obstacles is absolutely dependent on time, it is not justified by conventional turbulent models based on average time, so the use of direct solution of Navier Stocks equations is inevitable. One of the present models which can solve time-dependent Navier Stocks equations in wide range of Reynolds numbers, is Random Vortex Method (RVM). Since in this method velocity field is calculated momentarily, it can be used to simulate turbulent flows with a time-dependent nature. In this paper vorticity equations gained from Navier Stocks equations are solved in both convection and diffusion phases. In this study, the flow on two cylinders with Re=140000 is investigated and field of average and momentary velocity is shown along with streamlines. Also by drawing momentary distribution of vortex fields and streamlines it is possible to provide a revealing presentation of vortexes behind cylinders.

کلیدواژه ها:

Conformal Mapping ، Potential & TurbulentFlow ، Vortex