Ansys CFX – Flow around a Cylinder / Parameters DesignPoint (DP)

Source: FSU

External flows past objects have been studied extensively because of their many practical applications.  For example, airfoils are made into streamline shapes in order to increase the lifts, and at the same time, reducing the aerodynamic drags exerted on the wings.  On the other hand, flow past a blunt body, such as a circular cylinder, usually experiences boundary layer separation and very strong flow oscillations in the wake region behind the body.  In certain Reynolds number range, a periodic flow motion will develop in the wake as a result of boundary layer vortice being shed alternatively from either side of the cylinder.  This regular pattern of vortices in the wake is called a Karman vortex street.  It creates an oscillating flow at a discrete frequency that is correlated to the Reynolds number of the flow.   The periodic nature of the vortex shedding phenomenon can sometimes lead to unwanted structural vibrations, especially when the shedding frequency matches one of the resonant frequencies of the structure.  One example is the famous Tacoma Narrow bridge incident and this topic has been discussed in great details in the Tacoma bridge link.  In this presentation, we are going to investigate the flow past a circular cylinder and study the turbulent wake flow field using the Particle Image Velocimetry (PIV) technique.  Based on the PIV velocity field measurements and other reference information, a comprehensive discussion about many important flow concepts such as: boundary layer flow separation, wake flow, vortex shedding, vortex-induced oscillations, aerodynamic loading, momentum balance, and the lift and drag forces on an immerse body, will be given in the following section.

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In this tutorial you will learn to simulate aflow around a cylinder with Workbench parameters in 2D using ANSYS CFX. First, we will build a geometry and then we will generate the mesh using a structured mesh in Ansys Meshing. You can download the geometry from this link.