PRELIMINARY ANALYSIS OF FLOW OVER A CIRCULAR CYLINDER USING CFD

Resumo

The flow of air over a circular cylinder can be observed in many civil engineering problems. Tall
buildings, towers and silos can be subject to strong winds that can impact the structure local or global stability.
The flow over a cylindrical structure is a dynamic problem with transient response characterized by vortex
shedding. If the Reynolds number is sufficiently high, an alternate vortex shedding pattern is formed, known as
von Karman vortex street. In this scenario, the flow applies dynamic drag and lift forces on the structure. This
paper presents a methodology to simulate the fluid flow over a circular cylinder and compute the drag and lift
coefficients using Computational Fluid Dynamics (CFD). A two-dimensional cross-section of a structure is
modelled in ANSYS Fluent applying the proper boundary conditions. The pressure fields are computed from the
simulations and numerical integration is used to obtain the drag and lift coefficients. From the simulations, the
streamlines, and pressure fields can also be obtained and plotted. Geometry, mesh and time step size independence
studies are conducted to ensure convergence. The results are compared to numerical data found in the literature.