Abstract
The flow past a cylinder is a classical problem in flow physics. In a certain range of Reynolds number, there will be Karman vortex street phenomenon in the wake of a cylinder, which will greatly increase the pressure drag of the cylinder. By controlling the vortex shedding phenomenon, drag reduction of the cylinder could be effectively realized. In this paper, a NACA0012 airfoil with pitching oscillation is placed downstream of the cylinder. Based on the tight coupling method, kinematics equations and Navier–Stokes equations in the arbitrary Lagrangian–Eulerian form are solved. Firstly, the effect of airfoil oscillation period and the distance between airfoil leading edge and cylinder center (x/D) are studied respectively, especially considering the aspects of vortex shedding and drag reduction effect. Besides, the vortex interaction in the flow field around the airfoil and cylinder is analyzed in detail. It is found that the NACA0012 airfoil with pitching oscillation can change the period of vortex shedding. Moreover, it can also increase the drag reduction rate to as high as 50.5%, which presents a certain application prospect in the engineering drag reduction field, e.g., for launch vehicles, ship masts, submarine pipelines, etc.
Highlights
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Flow past a cylinder is a common phenomenon of flow physics in nature and engineering practices, e.g., in launch vehicles [1,2], ship masts [3,4], submarine pipelines [5,6], and fluidics at the micro and nano scale [7,8]
Within the range of Reynolds number common in engineering practices, an alternately shedding Karman vortex street can be generated in the wake of a cylinder
Summary
Flow past a cylinder is a common phenomenon of flow physics in nature and engineering practices, e.g., in launch vehicles [1,2], ship masts [3,4], submarine pipelines [5,6], and fluidics at the micro and nano scale [7,8]. Within the range of Reynolds number common in engineering practices, an alternately shedding Karman vortex street can be generated in the wake of a cylinder. Pressure drag contributes most sources of resistance to the cylinder. On this basis, drag reduction can be effectively achieved in the cylinder via controlling the vortex shedding phenomenon
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
