Simulation of Starting and Stopping Vortices of an Airfoil

Abstract

When the flow around a streamlined body is accelerated or decelerated,starting and stopping vortices are shed from the trailing edge of the body, respectively. In this work, the transient flow around a NACA4612 airoil profile was analyzed and simulated at Re = 1000 and a = 16 paying especial attention to the starting and stopping vortices shed from the airfoil. A detailed review of the underliying physics of the generation of lift was presented with focus on the importance of viscosity as the essential factor for the generation of lift. The incompressible Navier-Stokes equations with constant density and viscosity in an inertial frame of reference were solved with OpenFOAM using a linear upwind finite volume method (FVM) for the space discretization and the implicit Euler method for the time integration. The results were verified using the Kelvin circulation theorem. Three flow animations were prepared with the simulation results and compared with the historical flow visualizations from Prandtl.