عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Analysis of the flow passing cylindrical obstacles is one of the basic issues in fluid dynamics and is of great importance. Many surveys have been conducted 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 depended on time, the conventional turbulent models which are based on average time, do not justify, and the use of direct solution of Navier Stocks equations is inevitable. One of the presented 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 instantly calculated, 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 three cylinders with Re=140000 is investigated and field of average and instant velocity is shown along with streamlines. Also by drawing instant distribution of vortex fields and streamlines, it is possible to provide a revealing presentation of vortex behind cylinders.