Flow past Bluff Bodies by a Vortex Method

摘要

A review of the literature on vortex methods for the representation of vortexsheets and the literature in two dimensional viscous incompressible flow past bluff bodies, mainly the circular cylinder, both experimental and numerical, with emphasis on the use of vortex methods, is presented. An algorithm for the transport of vorticity in two dimensional incompressible flow past a circular cylinder is considered. The algorithm considered only Reynolds numbers (Re) 20, 40, 100 and 200. The physical predictions of this approach for uniform flow past a circular cylinder over a wider range of Re, and to mathematically develop and apply the algorithm to other flows and bodies, are further investigated. The working Re of the method is extended up to 1000, and down to 2. Steady symmetric fully developed flow is studied for Re between 2 and 500, and the symmetric starting flow is examined for Re greater than or equal to 100 and less than or equal to 500. A rotating cylinder is considered next for Re greater than or equal to 5 and less than or equal to 200. The algorithm is developed for a noncircular body, and the flow past an elliptic cylinder at incidence is studied for Re greater than or equal to 15 and less than or equal to 200. The results from the above works are compared, where possible, with the available literature. This study led to the development of a versatile algorithm for two dimensional bluff body flows which can be adapted for application to arbitrary body shapes and used to calculate aerodynamic forces, Strouhal numbers, and vorticity distributions in the flow field and to the discovery of various interesting physical phenomena.